Fix playback with invalid files that don't set the continuation flag for

pages that continue packets started in prior pages.
Fixes issue1248

Originally committed as revision 21688 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/oggdec.h

@@ -71,6 +71,7 @@ struct ogg_stream {
     int header;
     int nsegs, segp;
     uint8_t segments[255];
+    int incomplete; ///< whether we're expecting a continuation in the next page
     int page_end;   ///< current packet is the last one completed in the page
     void *private;
 };