fix issue 5167: Add Finalizer when create snat

Author: liwenjian

pkg/controller/vpc_nat_gw_nat.go

@@ -961,8 +961,7 @@ func (c *Controller) handleDelIptablesSnatFinalizer(key string) error {
 		return nil
 	}
 	newIptablesSnat := cachedIptablesSnat.DeepCopy()
-	controllerutil.RemoveFinalizer(newIptablesSnat, util.DepreciatedFinalizerName)
-	controllerutil.RemoveFinalizer(newIptablesSnat, util.KubeOVNControllerFinalizer)
+	controllerutil.AddFinalizer(newIptablesSnat, util.KubeOVNControllerFinalizer)
 	patch, err := util.GenerateMergePatchPayload(cachedIptablesSnat, newIptablesSnat)
 	if err != nil {
 		klog.Errorf("failed to generate patch payload for iptables snat '%s', %v", cachedIptablesSnat.Name, err)