title: Jenkins job pipeline type clone only gdsl file without clone the whole git repository
body: <p>To summerize the issue, I have git repository for example called Repo_A.<br/>
  Repo_A contains:<br/></p>
  
  <pre><code>Repo_A:
  ---&gt; release-pipeline.gdsl
  ---&gt; src/
  ---&gt; pom.xml
  </code></pre>
  
  <p><em>release-pipeline.gdsl</em> content:</p>
  
  <pre><code>node(params.node) {
      stage('Build Source Code') {
          sh 'pwd'
          sh 'ls -l'
          sh 'mvn clean compile package'
      }
  }
  </code></pre>
  
  <p>The output of the stage is the following (Jenkins project name Repo_A_CI_Project):</p>
  
  <pre><code>Started by user MyUser
  Obtained release-pipeline.gdsl from git git@github.com:Repo_A.git
  Running in Durability level: MAX_SURVIVABILITY
  [Pipeline] node
  Running on myServer in /home/MyHome/jenkins_agent/workspace/Repo_A_CI_Project
  [Pipeline] {
  [Pipeline] stage
  [Pipeline] { (Build Source Code)
  [Pipeline] sh
  + pwd
  /home/MyHome/jenkins_agent/workspace/Repo_A_CI_Project
  [Pipeline] sh
  + ls -l
  total 0
  [Pipeline] sh
  + mvn clean compile package
  [INFO] Scanning for projects...
  [INFO] ------------------------------------------------------------------------
  [INFO] BUILD FAILURE
  [INFO] ------------------------------------------------------------------------
  [INFO] Total time: 3.735 s
  [INFO] Finished at: 2019-10-20T09:26:34+00:00
  [INFO] Final Memory: 25M/1963M
  [INFO] ------------------------------------------------------------------------
  [ERROR] The goal you specified requires a project to execute but there is no POM in this directory (/home/MyHome/jenkins_agent/workspace/Repo_A_CI_Project). Please verify you invoked Maven from the correct directory. -&gt; [Help 1]
  [ERROR] 
  [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
  [ERROR] Re-run Maven using the -X switch to enable full debug logging.
  [ERROR] 
  [ERROR] For more information about the errors and possible solutions, please read the following articles:
  [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MissingProjectException
  [Pipeline] }
  [Pipeline] // stage
  [Pipeline] }
  [Pipeline] // node
  [Pipeline] End of Pipeline
  [BFA] Scanning build for known causes...
  [BFA] No failure causes found
  [BFA] Done. 0s
  ERROR: script returned exit code 1
  Finished: FAILURE
  </code></pre>
  
  <p>The problem here is that Jenkins Pipeline doens't clone the whole Repo_A repository contents. It's only obtain the gdsl file <code>release-pipeline.gdsl</code>. </p>
  
  <p>The job is pipeline type, I already set the right config for this project and what is the git repo should pull it. </p>
  
  <p>Previously it was working without issue and pull the whole repo and consider the execution place on the root of the repo to start execute stage's commands.</p>
  
  <p>As you can see from the log, I used <code>ls -l</code> to view the content and it show 0 content. </p>
  
  <pre><code>[Pipeline] sh
  + ls -l
  total 0
  [Pipeline]
  </code></pre>
  
  <p>I expect to see like that</p>
  
  <pre><code>[Pipeline] sh
  + ls
  release-pipeline.gdsl src/ pom.xml
  [Pipeline]
  </code></pre>
  
  <p>in Jenkins log, the only thing that I see is this simple message.</p>
  
  <pre><code>org.jenkinsci.plugins.githubautostatus.GithubNotificationConfig log
  INFO: Could not find commit sha - status will not be provided for this build
  </code></pre>
  
  <p>I'm using this approach since it's simple to pull the Jenkins build file (<code>release-pipeline.gdsl</code>) as well as the other content of repo to build directly without extra steps. </p>
  
  <p>Appreciate your help. </p>