Fix gesture nav after CSD warning dialog is shown.

This CL fixes a gesture navigation bug that would happen right after the
CSD warning dialog was shown and until any other SystemUIDialog would be
shown. See http://b/276821983#comment20 for details.

Bug: 276821983
Test: Manual, cherry-pick http://ag/22573874 and click the Internet tile
      to show the CSD dialog. Swiping up to home from an app should work
      as expected.
Change-Id: Ib238823a9b1d273202ebeded7de21e2f17baa063

packages/SystemUI/src/com/android/systemui/volume/CsdWarningDialog.java

@@ -199,6 +199,7 @@ public class CsdWarningDialog extends SystemUIDialog
 
     @Override
     protected void onStop() {
+        super.onStop();
         synchronized (mTimerLock) {
             if (mCancelScheduledNoUserActionRunnable != null) {
                 mCancelScheduledNoUserActionRunnable.run();