Kubelet should garbage collect dead pods

The sync loop should check for terminated pods that are no longer
running and clear them. The status loop should never write status
if the pod UID changes. Mirror pods should be deleted immediately
rather than gracefully.

pkg/kubelet/mirror_client.go

@@ -64,7 +64,7 @@ func (mc *basicMirrorClient) DeleteMirrorPod(podFullName string) error {
 		return err
 	}
 	glog.V(4).Infof("Deleting a mirror pod %q", podFullName)
-	if err := mc.apiserverClient.Pods(namespace).Delete(name, nil); err != nil {
+	if err := mc.apiserverClient.Pods(namespace).Delete(name, api.NewDeleteOptions(0)); err != nil {
 		glog.Errorf("Failed deleting a mirror pod %q: %v", podFullName, err)
 	}
 	return nil