Fix not delivering result to fragment using SubSettingLauncher

- Call Fragment.startActivityForResult instead of Activity's one

Test: make RunSettingsRoboTests
Test: App info page is closed instantly after uninstalling the package
Change-Id: If29c097c988101f89dcd9d0a5c1c68deed04eaa9

src/com/android/settings/core/SubSettingLauncher.java

@@ -164,7 +164,7 @@ public class SubSettingLauncher {
     }
 
     private void launchForResult(Fragment listener, Intent intent, int requestCode) {
-        listener.getActivity().startActivityForResult(intent, requestCode);
+        listener.startActivityForResult(intent, requestCode);
     }
 
     /**