Bugzilla Migration: Update (most) urls to bugs.libreoffice.org

This commit updates most urls from bugs.freedesktop.org ->
bugs.libreoffice.org. We're unable to change $Bugzilla_uri ahead of
time because we'll fail the certificate check, so that change will
have to be merged-in on the day of the Bugzilla migration.
Merge pull request #5 from colonelqubit/master

Bugzilla Migration: Update (most) urls to bugs.libreoffice.org