WPS context menu: Set modified after reshuffle

Prevents incorrect bookmarking of permanently
(not just temporarily) shuffled playlists, which
need to be resaved, before they can be correctly
bookmarked.

Change-Id: I157d3be9d05117f7566ca72f3e736f96b42a165d

apps/onplay.c

@@ -209,6 +209,7 @@ static bool shuffle_playlist(void)
         return false;
     playlist_sort(NULL, true);
     playlist_randomise(NULL, current_tick, true);
+    playlist_set_modified(NULL, true);
 
     return false;
 }