volume integration: wait for PVs before creating PVCs

The test should wait until all volumes are processed by volume controller (i.e.
in the controller cache) before creating a PVC.

Without that, the "best" matching PV could not be in the cache and controller
might bind the PVC to suboptiomal one.

This fixes integration test flake "Bind mismatch! Expected pvc-2 capacity
50000000000 but got pvc-2 capacity 52000000000".

test/integration/persistent_volumes_test.go

@@ -250,6 +250,7 @@ func TestPersistentVolumeMultiPVs(t *testing.T) {
 		if err != nil {
 			t.Errorf("Failed to create PersistentVolume %d: %v", i, err)
 		}
+		waitForPersistentVolumePhase(testClient, pvs[i].Name, watchPV, api.VolumeAvailable)
 	}
 	t.Log("volumes created")