title: sam build --use-container failed but sam build is success
body: <p>The issue happens in the following setup:</p>
  
  <ol>
  <li>Virtual Machine launched in OpenStack</li>
  <li>OS is Ubuntu 16.04 LTS</li>
  <li>Python version 3.7.6 with virtualenv installed</li>
  <li>SAM CLI version  0.39.0</li>
  </ol>
  
  <p>To replicate the issues, you may use the above setup and perform the following steps:</p>
  
  <ol>
  <li><code>$ sam init</code></li>
  <li><code>$ Choice: 1</code></li>
  <li><code>$ Runtime 9</code>   Select python3.7</li>
  <li><code>$ Project name[sam-app]</code>: sam-app</li>
  <li><code>$ Template selection: 1</code>  Select Hello World Example</li>
  </ol>
  
  <p>Wait for the application to be generated. </p>
  
  <ol start="6">
  <li><code>$ cd sam-app</code></li>
  <li><code>$ python3 -m virtualenv venv</code></li>
  <li><code>$ source venv/bin/activate</code> </li>
  <li><code>$(venv) source venv/bin/activate</code> </li>
  <li><code>$(venv) sam build</code></li>
  </ol>
  
  <p>The following output shall appear:</p>
  
  <pre><code>Building resource 'HelloWorldFunction'
  Running PythonPipBuilder:ResolveDependencies
  Running PythonPipBuilder:CopySource
  
  Build Succeeded
  
  Built Artifacts  : .aws-sam/build
  Built Template   : .aws-sam/build/template.yaml
  
  Commands you can use next
  =========================
  [*] Invoke Function: sam local invoke
  [*] Deploy: sam deploy --guided
  
  </code></pre>
  
  <p>However, if the <code>--use-container</code> flag is used, the following error will appear</p>
  
  <pre><code>Telemetry endpoint configured to be https://aws-serverless-tools-telemetry.us-west-2.amazonaws.com/metrics
  'build' command is called
  Starting Build inside a container
  No Parameters detected in the template
  2 resources found in the template
  Found Serverless function with name='HelloWorldFunction' and CodeUri='hello_world/'
  Building resource 'HelloWorldFunction'
  
  Fetching lambci/lambda:build-python3.7 Docker container image......
  Mounting /home/ubuntu/test/sam-app/hello_world as /tmp/samcli/source:ro,delegated inside runtime container
  Using the request object from command line argument
  Loading workflow module 'aws_lambda_builders.workflows'
  Registering workflow 'PythonPipBuilder' with capability 'Capability(language='python', dependency_manager='pip', application_framework=None)'
  Registering workflow 'NodejsNpmBuilder' with capability 'Capability(language='nodejs', dependency_manager='npm', application_framework=None)'
  Registering workflow 'RubyBundlerBuilder' with capability 'Capability(language='ruby', dependency_manager='bundler', application_framework=None)'
  Registering workflow 'GoDepBuilder' with capability 'Capability(language='go', dependency_manager='dep', application_framework=None)'
  Registering workflow 'GoModulesBuilder' with capability 'Capability(language='go', dependency_manager='modules', application_framework=None)'
  Registering workflow 'JavaGradleWorkflow' with capability 'Capability(language='java', dependency_manager='gradle', application_framework=None)'
  Registering workflow 'JavaMavenWorkflow' with capability 'Capability(language='java', dependency_manager='maven', application_framework=None)'
  Registering workflow 'DotnetCliPackageBuilder' with capability 'Capability(language='dotnet', dependency_manager='cli-package', application_framework=None)'
  Found workflow 'PythonPipBuilder' to support capabilities 'Capability(language='python', dependency_manager='pip', application_framework=None)'
  Running workflow 'PythonPipBuilder'
  Running PythonPipBuilder:ResolveDependencies
  calling pip download -r /tmp/samcli/source/requirements.txt --dest /tmp/samcli/scratch
  PythonPipBuilder:ResolveDependencies failed
  Traceback (most recent call last):
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/actions.py", line 42, in execute
      requirements_path=self.manifest_path,
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/packager.py", line 137, in build_dependencies
      self._dependency_builder.build_site_packages(requirements_path, artifacts_dir_path, scratch_dir_path)
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/packager.py", line 198, in build_site_packages
      wheels, packages_without_wheels = self._download_dependencies(scratch_directory, requirements_filepath)
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/packager.py", line 222, in _download_dependencies
      deps = self._download_all_dependencies(requirements_filename, directory)
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/packager.py", line 305, in _download_all_dependencies
      self._pip.download_all_dependencies(requirements_filename, directory)
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/packager.py", line 594, in download_all_dependencies
      raise NoSuchPackageError(str(package_name))
  aws_lambda_builders.workflows.python_pip.packager.NoSuchPackageError: Could not satisfy the requirement: requests
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflow.py", line 269, in run
      action.execute()
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/actions.py", line 45, in execute
      raise ActionFailedError(str(ex))
  aws_lambda_builders.actions.ActionFailedError: Could not satisfy the requirement: requests
  Builder workflow failed
  Traceback (most recent call last):
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/actions.py", line 42, in execute
      requirements_path=self.manifest_path,
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/packager.py", line 137, in build_dependencies
      self._dependency_builder.build_site_packages(requirements_path, artifacts_dir_path, scratch_dir_path)
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/packager.py", line 198, in build_site_packages
      wheels, packages_without_wheels = self._download_dependencies(scratch_directory, requirements_filepath)
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/packager.py", line 222, in _download_dependencies
      deps = self._download_all_dependencies(requirements_filename, directory)
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/packager.py", line 305, in _download_all_dependencies
      self._pip.download_all_dependencies(requirements_filename, directory)
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/packager.py", line 594, in download_all_dependencies
      raise NoSuchPackageError(str(package_name))
  aws_lambda_builders.workflows.python_pip.packager.NoSuchPackageError: Could not satisfy the requirement: requests
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflow.py", line 269, in run
      action.execute()
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflows/python_pip/actions.py", line 45, in execute
      raise ActionFailedError(str(ex))
  aws_lambda_builders.actions.ActionFailedError: Could not satisfy the requirement: requests
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/__main__.py", line 126, in main
      mode=params.get("mode", None),
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/builder.py", line 125, in build
      return workflow.run()
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflow.py", line 76, in wrapper
      func(self, *args, **kwargs)
    File "/var/lang/lib/python3.7/site-packages/aws_lambda_builders/workflow.py", line 276, in run
      raise WorkflowFailedError(workflow_name=self.NAME, action_name=action.NAME, reason=str(ex))
  aws_lambda_builders.exceptions.WorkflowFailedError: PythonPipBuilder:ResolveDependencies - Could not satisfy the requirement: requests
  Build inside container returned response {"jsonrpc": "2.0", "id": 1, "error": {"code": 400, "message": "PythonPipBuilder:ResolveDependencies - Could not satisfy the requirement: requests"}}
  
  Build Failed
  Sending Telemetry: {'metrics': [{'commandRun': {'awsProfileProvided': False, 'debugFlagProvided': True, 'region': '', 'commandName': 'sam build', 'duration': 107282, 'exitReason': 'BuildError', 'exitCode': 1, 'requestId': '62d1fc73-70e5-4592-8c78-8fa273684592', 'installationId': 'ce8ffa14-684f-4628-97fe-288848fcf73d', 'sessionId': '4ca5bb42-5cf1-4ae5-89ad-9ed00366fefb', 'executionEnvironment': 'CLI', 'pyversion': '3.7.6', 'samcliVersion': '0.39.0'}}]}
  HTTPSConnectionPool(host='aws-serverless-tools-telemetry.us-west-2.amazonaws.com', port=443): Read timed out. (read timeout=0.1)
  Error: PythonPipBuilder:ResolveDependencies - Could not satisfy the requirement: requests
  
  </code></pre>