title: Polling SCM: Jenkins Pipeline Script not waking up on SVN Commit
body: <p>I am new to Jenkins Pipeline Script, I have moved my FreeStyle project to a Pipeline but am not able to get my Master server to wake up when I make a commit to my SVN repo. Here is my first couple of lines and where my SVN credentials are declared:</p>
  
  <pre><code>node {
  try {
      notifyBuild('STARTED')
  
  stage('Checkout') {
  checkout([$class: 'SubversionSCM',
      additionalCredentials: [], 
      excludedCommitMessages: '', 
      excludedRegions: '', 
      excludedRevprop: '', 
      excludedUsers: 'buildbot', 
      filterChangelog: false, 
      ignoreDirPropChanges: false, 
      includedRegions: '', 
      locations: [[credentialsId: 'my-login-id-creds-are-here', 
          depthOption: 'infinity', 
          ignoreExternalsOption: true, 
          local: '.', 
          remote: "http://this.is.myweburl.com/svn/path/to/branch"]],
      workspaceUpdater: [$class: 'UpdateUpdater']])
  }
  </code></pre>
  
  <p>Is there a way to poll SCM?</p>
  
  <p>Let me know if you have any questions. </p>
  
  <p>Thanks!</p>