Add support for 'rbt patch -c' for Mercurial repositories
Review Request #6090 — Created July 9, 2014 and submitted — Latest diff uploaded
Implement create_commit() in mercurial.py to support committing using information from the review request.
Posted a patch to Review Board, popped it off the queue, ran 'rbt patch -c <review_id>' and verified that the changeset was correctly committed.