title: Jenkins BUILD_USER_ID MissingPropertyException for Pipeline Trigerred by Git SCM
body: <p>I need to get <code>BUILD_USER_ID</code> from Jenkins pipeline, and successfully implemented using this tutorial: <a href="https://stackoverflow.com/questions/35902664/get-user-name-from-jenkins-workflow-pipeline-plugin">here</a></p>
  
  <p>It works when triggered manually by user, but error returned when triggered by GitSCM.</p>
  
  <p><code>groovy.lang.MissingPropertyException: No such property: BUILD_USER_ID for class: groovy.lang.Binding
  </code></p>
  
  <p>Please help.</p>