buildbot & buildbotcustom moved to Mercurial

Both mozilla/tools/buildbotcustom and mozilla/tools/buildbot have now official moved to their new homes in Mercurial, http://hg.mozilla.org/build/buildbotcustom/ and http://hg.mozilla.org/build/buildbot/ respectively. The buildbotcustom CVS module will be deleted at the end of this week. We will be keeping the buildbot one for the time being because we have a Buildbot still using it, but all future work should be done against the Mercurial repository.