Merge "Don't touch empty wallpaper sentinel every backup."

            // We always back up this 'empty' file to ensure that the absence of

            // storable wallpaper imagery still produces a non-empty backup data

            // stream, otherwise it'd simply be ignored in preflight.

            if (!empty.exists()) {

                FileOutputStream touch = new FileOutputStream(empty);

                touch.close();

            }

            fullBackupFile(empty, data);

            SharedPreferences prefs = getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);