Replace remaining occurances of av_free_packet with av_packet_unref

libavdevice/decklink_dec.cpp

@@ -48,7 +48,7 @@ static void avpacket_queue_flush(AVPacketQueue *q)
     pthread_mutex_lock(&q->mutex);
     for (pkt = q->first_pkt; pkt != NULL; pkt = pkt1) {
         pkt1 = pkt->next;
-        av_free_packet(&pkt->pkt);
+        av_packet_unref(&pkt->pkt);
         av_freep(&pkt);
     }
     q->last_pkt   = NULL;