Fix settings crash during pathological rotate.

Bug:14281882
Change-Id: If30a3e8eea35564853fc12c03f8ab63c258310c9

src/com/android/settings/notification/AppNotificationSettings.java

@@ -113,6 +113,12 @@ public class AppNotificationSettings extends ListFragment {
         mListViewState = getListView().onSaveInstanceState();
     }
 
+    @Override
+    public void onDestroyView() {
+        super.onDestroyView();
+        mListViewState = null;  // you're dead to me
+    }
+
     @Override
     public void onResume() {
         super.onResume();