re-enable cascading deployment

Signed-off-by: Jess Frazelle <acidburn@google.com>

hack/make-rules/test-cmd-util.sh

@@ -2094,12 +2094,7 @@ run_deployment_tests() {
   # Deletion of both deployments should not be blocked
    kubectl delete deployment nginx2 "${kube_flags[@]}"
   # Clean up
-  # TODO: cascading deletion of deployments is failing.
-  # TODO: re-enable this once https://github.com/kubernetes/kubernetes/issues/40433 is fixed
-  #   kubectl delete deployment nginx "${kube_flags[@]}"
-  # TODO: remove these once https://github.com/kubernetes/kubernetes/issues/40433 is fixed
-    kubectl delete deployment nginx --cascade=false "${kube_flags[@]}" 
-    kubectl delete replicaset --all "${kube_flags[@]}"
+  kubectl delete deployment nginx "${kube_flags[@]}"
 
   ### Set image of a deployment
   # Pre-condition: no deployment exists