title: problems installing pandas module with pip on mac
body: <p>I have 2 python installations on my mac osx. </p>
  
  <pre><code>$ which python
  /usr/bin/python
  
  $ which python3
  /Library/Frameworks/Python.framework/Versions/3.4/bin/python3
  
  $ pip install --upgrade setuptools
  Collecting setuptools
    Downloading https://files.pythonhosted.org/packages/37/06/754589caf971b0d2d48f151c2586f62902d93dc908e2fd9b9b9f6aa3c9dd/setuptools-40.6.3-py2.py3-none-any.whl (573kB)
      100% |████████████████████████████████| 655kB 1.5MB/s 
  Installing collected packages: setuptools
    Found existing installation: setuptools 2.1
      Uninstalling setuptools-2.1:
        Successfully uninstalled setuptools-2.1
  Successfully installed setuptools-40.6.3
  $ which pip
  /Library/Frameworks/Python.framework/Versions/3.4/bin/pip
  
  $ pip -V
  pip 18.1 from /Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/pip (python 3.4)
  </code></pre>
  
  <p>I can install modules with pip fine. for example
  $ python3 -m pip install --user tensorflow
  Successfully installed absl-py-0.6.1 astor-0.7.1 gast-0.2.0 grpcio-1.17.1 markdown-3.0.1 protobuf-3.6.1 tensorboard-1.12.1 tensorflow-1.12.0 termcolor-1.1.0 werkzeug-0.14.1</p>
  
  <p>but when i try the same with pandas
  $ python3 -m pip install --user pandas</p>
  
  <p>it goes through till the end by collecting and downloading dependencies, but errors out with the following error. </p>
  
  <pre><code>Collecting pandas
    Downloading https://files.pythonhosted.org/packages/08/01/803834bc8a4e708aedebb133095a88a4dad9f45bbaf5ad777d2bea543c7e/pandas-0.22.0.tar.gz (11.3MB)
      100% |████████████████████████████████| 11.4MB 1.5MB/s 
    Installing build dependencies ... done
      Complete output from command python setup.py egg_info:
      Download error on https://pypi.org/simple/numpy/: [SSL: TLSV1_ALERT_PROTOCOL_VERSION] tlsv1 alert protocol version (_ssl.c:600) -- Some packages may not be found!
      Couldn't find index page for 'numpy' (maybe misspelled?)
      Download error on https://pypi.org/simple/: [SSL: TLSV1_ALERT_PROTOCOL_VERSION] tlsv1 alert protocol version (_ssl.c:600) -- Some packages may not be found!
      No local packages or working download links found for numpy&gt;=1.9.0
      Traceback (most recent call last):
        File "&lt;string&gt;", line 1, in &lt;module&gt;
        File "/private/var/folders/d5/k1w6m6xj5g727x952sdkkc1r0000gn/T/pip-install-r4n38agj/pandas/setup.py", line 743, in &lt;module&gt;
          **setuptools_kwargs)
        File "/private/var/folders/d5/k1w6m6xj5g727x952sdkkc1r0000gn/T/pip-build-env-fqe1gkak/lib/python3.4/site-packages/setuptools/__init__.py", line 142, in setup
          _install_setup_requires(attrs)
        File "/private/var/folders/d5/k1w6m6xj5g727x952sdkkc1r0000gn/T/pip-build-env-fqe1gkak/lib/python3.4/site-packages/setuptools/__init__.py", line 137, in _install_setup_requires
          dist.fetch_build_eggs(dist.setup_requires)
        File "/private/var/folders/d5/k1w6m6xj5g727x952sdkkc1r0000gn/T/pip-build-env-fqe1gkak/lib/python3.4/site-packages/setuptools/dist.py", line 586, in fetch_build_eggs
          replace_conflicting=True,
        File "/private/var/folders/d5/k1w6m6xj5g727x952sdkkc1r0000gn/T/pip-build-env-fqe1gkak/lib/python3.4/site-packages/pkg_resources/__init__.py", line 780, in resolve
          replace_conflicting=replace_conflicting
        File "/private/var/folders/d5/k1w6m6xj5g727x952sdkkc1r0000gn/T/pip-build-env-fqe1gkak/lib/python3.4/site-packages/pkg_resources/__init__.py", line 1063, in best_match
          return self.obtain(req, installer)
        File "/private/var/folders/d5/k1w6m6xj5g727x952sdkkc1r0000gn/T/pip-build-env-fqe1gkak/lib/python3.4/site-packages/pkg_resources/__init__.py", line 1075, in obtain
          return installer(requirement)
        File "/private/var/folders/d5/k1w6m6xj5g727x952sdkkc1r0000gn/T/pip-build-env-fqe1gkak/lib/python3.4/site-packages/setuptools/dist.py", line 653, in fetch_build_egg
          return cmd.easy_install(req)
        File "/private/var/folders/d5/k1w6m6xj5g727x952sdkkc1r0000gn/T/pip-build-env-fqe1gkak/lib/python3.4/site-packages/setuptools/command/easy_install.py", line 673, in easy_install
          raise DistutilsError(msg)
      distutils.errors.DistutilsError: Could not find suitable distribution for Requirement.parse('numpy&gt;=1.9.0')
  
      ----------------------------------------
  Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/d5/k1w6m6xj5g727x952sdkkc1r0000gn/T/pip-install-r4n38agj/pandas/
  </code></pre>
  
  <p>The issue seems to be that it is using Python where it should be using python3 in python setup.py egg_info</p>
  
  <p>how do i make sure that pip uses python3 in the scripts or if there is any other issues ?</p>