Use internal demuxer for Matroska files for now

Change the default demuxer back to the internal one at least until the
current lavf breakage with SSA/ASS subtitles is sorted out. There have
also been quite a few other regressions so maybe the lavf demuxer
should be tested a bit more before trying to make it the default again.

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@27551 b3059339-0415-0410-9bf9-f77b7e298cf2

libmpdemux/demux_lavf.c

@@ -183,7 +183,6 @@ static const char *preferred_list[] = {
     "mov,mp4,m4a,3gp,3g2,mj2",
     "mpc",
     "mpc8",
-    "matroska",
     NULL
 };