jenkinsci/hockeyapp-plugin — pull request #27 by Brantone (2014-12-16 08:55:15+00:00)
Title: Expand vars for null check.

Tackle https://issues.jenkins-ci.org/browse/JENKINS-26059
When using parameters, the field value won't be null; however, if the param is empty, the expanded value is also empty, which would be considered null.