Fix version parsing for Mercurial.
Review Request #3433 — Created Oct. 19, 2012 and submitted
Fix version parsing for Mercurial. Our version parsing was relying upon integers only in the version, and had a probably incorrect hack for handling "+" in the version number. Since Mercurial is a Python package following Python versioning rules, we should be using parse_version comparisons. This is a lot less fragile, and works with their new 1.4-rc release they just put out (which completely breaks Review Board today). This will be needed for an upcoming release soon.
Tested with the new Mercurial 1.4-RC release, which broke us tonight.