avi demux: don't disable tracks when they end.

Disabling the tracks like this is an immediate action that messes up --file-caching for instance. There may be some cases where it is appropriate, and some cases where a track should be removed, but not when a track ends. In that case the core is responsible for cleanup.

Tested in bugfix for normal avi, broken avi and repaired avi, but not with "streamed" avi.

Should close #2853

modules/demux/avi/avi.c

@@ -2461,7 +2461,6 @@ static int AVI_TrackStopFinishedStreams( demux_t *p_demux )
         if( tk->i_idxposc >= tk->i_idxnb )
         {
             tk->b_activated = false;
-            if( tk->p_es ) es_out_Control( p_demux->out, ES_OUT_SET_ES_STATE, tk->p_es, false );
         }
         else
         {