accountFragment: fix fragmentManager crash

Change-Id: I68467ab198ea5e53258c2d64b6ed2ab57f14b925

ring-android/app/src/main/java/cx/ring/fragments/GeneralAccountFragment.java

@@ -167,7 +167,7 @@ public class GeneralAccountFragment extends BasePreferenceFragment<GeneralAccoun
 
     @Override
     public void onDisplayPreferenceDialog(Preference preference) {
-        FragmentManager fragmentManager = getChildFragmentManager();
+        FragmentManager fragmentManager = getParentFragmentManager();
         if (fragmentManager.findFragmentByTag(DIALOG_FRAGMENT_TAG) != null) {
             return;
         }