New hook that disables mac spoof filtering

'macspoof' is a new hook that disables mac spoof filtering on a
VM basis.

Change-Id: I437d114dbd596e5f7e1a302a8f95c2ecdc4b4347
Signed-off-by: Assaf Muller <amuller@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/12833
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>