avformat/movenc: remove call to av_copy_packet_side_data() when concatenating eac3 syncframes

This generates a potential memory leak, and mixes side data from the last
packet with other properties from the first.

Keep all the properties from the first packet only in the output packet
instead.
Signed-off-by: James Almer <jamrial@gmail.com>

libavformat/movenc.c

@@ -520,8 +520,6 @@ concatenate:
         memcpy(info->pkt.data + info->pkt.size - pkt->size, pkt->data, pkt->size);
         info->num_blocks += num_blocks;
         info->pkt.duration += pkt->duration;
-        if ((ret = av_copy_packet_side_data(&info->pkt, pkt)) < 0)
-            goto end;
         if (info->num_blocks != 6)
             goto end;
         av_packet_unref(pkt);