I can also confirm this problem. Temporarily removing /etc/init.d/mdadm- raid seems to have worked fine for me as well.
I suggest this get marked with a higher priority. -- Upgrading mdadm package is impossible - can't upgrade while raid arrays active https://launchpad.net/bugs/60623 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
