mpegts: Fix potential memory leak in mpegts_read_packet()

This leak can happen in case of some error paths.

Found-by: Tanami, Ohad
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/mpegts.c

@@ -2066,6 +2066,7 @@ static int mpegts_read_packet(AVFormatContext *s,
     ts->pkt = pkt;
     ret = handle_packets(ts, 0);
     if (ret < 0) {
+        av_free_packet(ts->pkt);
         /* flush pes data left */
         for (i = 0; i < NB_PID_MAX; i++) {
             if (ts->pids[i] && ts->pids[i]->type == MPEGTS_PES) {