Enhance commit message for plugin/themes updates

[pdobrescu]

Please add in the commit message the initial version of the theme/plugin that was live before the update. So the commit message should look like:

Updated plugin Gitium from version x.x.x to y.y.y Updated theme TwentyFourteen from version x.y to z.t

This helps a lot in reporting bad plugin updates as well as debugging these updates errors. Probably helpful in other situations too.