[Jenkins-21947] m2release plugin support

This pull request adds support for the m2release plugin.

I successfully tested the plugin on Jenkins 1.532.1 and m2release plugin 0.12.0 running on Windows 2008 R2 SP1.

Also tested on Jenkins 1.480 m2release plugin 0.12.0 on Windows 7, but it seems that the m2release plugin does not support this old Jenkins version, couldn't get the m2release plugin to work.

Please review and merge.