The updates we had in the past (7719f7fand1faf610) broke the mdadm installer test and systems in the wild using mdraid because newer mdadm versions contained a self-referenc to its own store path. Instead of putting a big warning about updating in the package expression, let's just add allowedReferences so the build immediately fails if there is a self-reference. Signed-off-by: aszlig <aszlig@redmoonstudios.org>