Don't eat 403 in service controller

pkg/controller/service/servicecontroller.go

@@ -324,12 +324,10 @@ func (s *ServiceController) persistUpdate(service *v1.Service) error {
 			return nil
 		}
 		// TODO: Try to resolve the conflict if the change was unrelated to load
-		// balancer status. For now, just rely on the fact that we'll
-		// also process the update that caused the resource version to change.
+		// balancer status. For now, just pass it up the stack.
 		if errors.IsConflict(err) {
-			glog.Warningf("Not persisting update to service '%s/%s' that has been changed since we received it: %v",
+			return fmt.Errorf("Not persisting update to service '%s/%s' that has been changed since we received it: %v",
 				service.Namespace, service.Name, err)
-			return nil
 		}
 		glog.Warningf("Failed to persist updated LoadBalancerStatus to service '%s/%s' after creating its load balancer: %v",
 			service.Namespace, service.Name, err)