oggdec: chained oggs have timestamp discontinuities

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/oggdec.c

@@ -849,5 +849,5 @@ AVInputFormat ff_ogg_demuxer = {
     .read_seek      = ogg_read_seek,
     .read_timestamp = ogg_read_timestamp,
     .extensions     = "ogg",
-    .flags          = AVFMT_GENERIC_INDEX,
+    .flags          = AVFMT_GENERIC_INDEX | AVFMT_TS_DISCONT,
 };