pkg/start/start_integration_test: Do not assume "deleted" for ConfigMap lock release

From the godocs:

  $ grep -A5 '// HolderIdentity' vendor/k8s.io/client-go/tools/leaderelection/resourcelock/interface.go
    // HolderIdentity is the ID that owns the lease. If empty, no one owns this lease and
    // all callers may acquire. Versions of this library prior to Kubernetes 1.14 will not
    // attempt to acquire leases with empty identities and will wait for the full lease
    // interval to expire before attempting to reacquire. This value is set to empty when
    // a client voluntarily steps down.
    HolderIdentity       string      `json:"holderIdentity"`

The previous assumption that the release would involve ConfigMap
deletion was born with the test in 2b81f47 (cvo: Release our leader
lease when we are gracefully terminated, 2019-01-16, #87).

Author: wking

pkg/start/start_integration_test.go

@@ -560,7 +560,7 @@ func TestIntegrationCVO_gracefulStepDown(t *testing.T) {
 
 	// wait until the lock record exists
 	err = wait.PollImmediate(200*time.Millisecond, 60*time.Second, func() (bool, error) {
-		_, err := kc.CoreV1().ConfigMaps(ns).Get(ctx, ns, metav1.GetOptions{})
+		_, _, err := lock.Get(ctx)
 		if err != nil {
 			if errors.IsNotFound(err) {
 				return false, nil
@@ -582,26 +582,26 @@ func TestIntegrationCVO_gracefulStepDown(t *testing.T) {
 		t.Fatalf("no leader election events found in\n%#v", events.Items)
 	}
 
-	t.Logf("after the context is closed, the lock record should be deleted quickly")
+	t.Logf("after the context is closed, the lock should be released quickly")
 	cancel()
 	startTime := time.Now()
 	var endTime time.Time
 	// the lock should be deleted immediately
 	err = wait.PollImmediate(100*time.Millisecond, 10*time.Second, func() (bool, error) {
-		_, err := kc.CoreV1().ConfigMaps(ns).Get(ctx, ns, metav1.GetOptions{})
-		if errors.IsNotFound(err) {
-			endTime = time.Now()
-			return true, nil
-		}
+		electionRecord, _, err := lock.Get(ctx)
 		if err != nil {
+			if errors.IsNotFound(err) {
+				return false, nil
+			}
 			return false, err
 		}
-		return false, nil
+		endTime = time.Now()
+		return electionRecord.HolderIdentity == "", nil
 	})
 	if err != nil {
 		t.Fatal(err)
 	}
-	t.Logf("lock deleted in %s", endTime.Sub(startTime))
+	t.Logf("lock released in %s", endTime.Sub(startTime))
 
 	select {
 	case <-time.After(time.Second):