Changes

openshift-sdn: ensure multicast rules are cleaned up when net namespace
is deleted
The VNID doesn't get removed from the internal map until after the
deletion handling is all done, but the code that handles cleaning out
the MC rules checks the VNID map, and of course finds the VNID still
there with MC enabled.
Fix that by deleting the VNID from the map first.
https://bugzilla.redhat.com/show_bug.cgi?id=1449058
 (commit: ba40a5b)