libavformat/demux.c: fix duration estimates with original FFmpeg mpeg…

…ts demuxer

I had fixed this previously, but the change must have been lost
in the move from utils.c to demux.c.

mythtv/external/FFmpeg/libavformat/demux.c

@@ -1900,7 +1900,8 @@ static void estimate_timings(AVFormatContext *ic, int64_t old_offset)
     }
 
     if ((!strcmp(ic->iformat->name, "mpeg") ||
-         !strcmp(ic->iformat->name, "mpegts")) &&
+         !strcmp(ic->iformat->name, "mpegts") ||
+         !strcmp(ic->iformat->name, "mpegts-ffmpeg")) &&
         file_size && (ic->pb->seekable & AVIO_SEEKABLE_NORMAL)) {
         /* get accurate estimate from the PTSes */
         estimate_timings_from_pts(ic, old_offset);