Update to m-r-p 2.5 to fix releasing issues with recent versions of git

Problem often mentioned on jenkinsci-dev mailing list
- https://groups.google.com/d/topic/jenkinsci-dev/qkmbl3HrYgk/discussion
- https://groups.google.com/d/topic/jenkinsci-dev/fyxXO0HXrGc/discussion
- https://groups.google.com/d/topic/jenkinsci-dev/Dt0c8aDGnd8/discussion