title: Gracefully stopping a build step (plugin) on build abort
body: <p>I have a plugin in Jenkins that operates a remote server via rest.<br>
  How can I send one last request to the server on build abort? Thus, gracefully finishing the work of the plugin?</p>
  
  <p>The only reference to the 'Abort sequence' that I found is <a href="https://wiki.jenkins-ci.org/display/JENKINS/Aborting+a+build">this</a>.
  Which makes me think that the procedure is very rough, and that I can't catch the signal before it terminates the child (my plugin).</p>