[FIXED JENKINS-22397] Allow a Trigger to be a DependencyDeclarer.
Merge branch 'master' of git://github.com/jenkinsci/jenkins into Trigger-DependencyDeclarer-JENKINS-22397
Merge pull request #1168 from jglick/Trigger-DependencyDeclarer-JENKINS-22397

[JENKINS-22397] Allow a Trigger to be a DependencyDeclarer