[player] Don't unselect disappeared speakers on exit/restart

With the new speaker selection philosophy we aim to preserve user choice, so we
shouldn't unselect speakers just because they happen to be switched off when
the server is restarted.

src/player.c

@@ -3545,8 +3545,6 @@ player(void *arg)
   if (!player_exit)
     DPRINTF(E_LOG, L_PLAYER, "Player event loop terminated ahead of time!\n");
 
-  db_speaker_clear_all();
-
   for (device = outputs_list(); device; device = device->next)
     {
       ret = db_speaker_save(device);