Revert "mpegts: Make sure we don't return uninitialized packets"

This change broke data streams, particularly DSMCC packets were
rejected which in turn broke MHEG Interactive Services e.g. 'Red
Button' services

This reverts commit 2ea63fc.
(cherry picked from commit 19f2d50)

mythtv/external/FFmpeg/libavformat/mpegts-mythtv.c

@@ -2930,7 +2930,6 @@ static int mpegts_read_packet(AVFormatContext *s,
     MpegTSContext *ts = s->priv_data;
     int ret, i;
 
-    pkt->size = -1;
     ts->pkt = pkt;
     ret = handle_packets(ts, 0);
     if (ret < 0) {
@@ -2949,8 +2948,6 @@ static int mpegts_read_packet(AVFormatContext *s,
         }
     }
 
-    if (!ret && pkt->size < 0)
-        ret = AVERROR(EINTR);
     return ret;
 }