Comment 4 for bug 1401937

Overall, I don't think this should be treated as High, as routing works as expected except the fact we have a couple of unused bridges hanging.

If we really want to see this fixed, we should either patch the kernel or hack nova-network (use brctl delbr instead of ip link delete+ ensure we've got a corresponding rootwrap rule). Neither of the solutions is going to be implemented in the maintenance release.