Add version number to commit message in merge-to-branch.

This is a step towards automatically rolling arbitrary trunk revisions into Chromium.

This also deprecates the bash scripts as they now start to divert.

BUG=
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/223093003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20465 ce2b1a6d-e550-0410-aec6-3dcde31c8c00