Merge pull request kubernetes#42657 from luxas/kubeadm_fix_dummy

Automatic merge from submit-queue

kubeadm: Delete the dummy Deployment properly

**What this PR does / why we need it**:

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes kubernetes/kubeadm#149

**Special notes for your reviewer**:

Earlier, the Pod created by the Deployment wasn't deleted. With this option it is.
As suggested by @deads2k, thank you!

This is a bug fix for v1.6

**Release note**:

```release-note
```
@mikedanese @jbeda @dmmcquay @pires @errordeveloper @deads2k @caesarxuchao

cmd/kubeadm/app/master/apiclient.go

@@ -139,9 +139,9 @@ func createAndWaitForADummyDeployment(client *clientset.Clientset) error {
 
 	fmt.Println("[apiclient] Test deployment succeeded")
 
-	falseVar := false
+	foreground := metav1.DeletePropagationForeground
 	if err := client.ExtensionsV1beta1().Deployments(metav1.NamespaceSystem).Delete("dummy", &metav1.DeleteOptions{
-		OrphanDependents: &falseVar,
+		PropagationPolicy: &foreground,
 	}); err != nil {
 		fmt.Printf("[apiclient] Failed to delete test deployment [%v] (will ignore)\n", err)
 	}