[BZ 1083479] - Second invocation of about dialog fails - creating the dialog from scratch (instead of using the cached instance that was causing the issue). Also adding a link to GitHub commit corresponding to the build number (only for RHQ).

(cherry picked from commit 177ee40d9251de5207d58bf417c51187bc7bd38c)
Signed-off-by: Mike Thompson <mithomps@redhat.com>