Fixed rollback of port-mirroring enabled nic during hotplugNic

During vm.py:hotplugNic, if the nic had port mirroring enabled
and setPortMirroring failed, then previously the rollback
tried to use self.hotunplugNic with a 2nd parameter but the method
only accepts one parameter, as it should.

Patch Set 2:
Fixed merge issues

Change-Id: I0289101bbd7cb84e79ca2f37568e98f2c9af279f
Signed-off-by: Assaf Muller <amuller@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/16400
Reviewed-by: Dan Kenigsberg <danken@redhat.com>