nanny: reset instead to rearm worker on disable

Reset interface worker on ifreload/ifdown to cleanup fsm state,
master / lower hierarchy references and requirements, so there
are no leftovers for the ifup part of ifreload that may change
e.g. lower link reference (vlan's underlying device changes)
with the new policy/config it is applying.

nanny/interface.c

@@ -88,7 +88,7 @@ ni_managed_netdev_disable(ni_managed_device_t *mdev)
 
 	ni_nanny_schedule_recheck(&mgr->down, w);
 	ni_nanny_unschedule(&mgr->recheck, w);
-	ni_ifworker_rearm(w);
+	ni_ifworker_reset(w);
 
 	mdev->monitor = FALSE;
 	return TRUE;