Last month I've created a tool which adds comments to Bugzilla when a commit message references a bug number. It was done as a proof of concept and didn't receive much attention at the time. Today I'm happy to announce the existence of GitHub Bugzilla Hook.
I've used David Shea's GitHub Email Hook as my starting template and only modified it where needed. GitHub Bugzilla Hook will examine push data and post comments for every unique bug+branch combination. Once a comment for that particular bug+branch combination is made, new ones will not be posted, even if later commits reference the same bug. My main assumption is commits which are related to a bug will be pushed together most of the times so there shouldn't be lots of noise in Bugzilla.
See rhbz#1274703 for example of how the comments look. The parser behavior is taken from anaconda and conforms to the style the Red Hat Installer Engineering Team uses. Hopefully you find it useful as well.
My next step is to find a hosting place for this script and hook it up with the rhinstaller GitHub repos!