Don't print awkward negative seek message when playing directory

This was caused by a demuxer trying to undo the header read when probing
for its file format. This is pointless in any case, because the core
demuxer code seeks back to the start of the file when initializing a
demuxer.

libmpdemux/demux_lmlm4.c

@@ -181,7 +181,6 @@ static int lmlm4_check_file(demuxer_t* demuxer)
     mp_msg(MSGT_DEMUX, MSGL_V, "Checking for LMLM4 Stream Format\n");
 
     if(getFrame(demuxer, &frameInfo)!=1){
-	stream_skip(demuxer->stream,-8);
         mp_msg(MSGT_DEMUX, MSGL_V, "LMLM4 Stream Format not found\n");
         return 0;
     }