memleak found by ("wxWindows_study" <quicktime2008 at hotmail dot com>)

Originally committed as revision 3396 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffplay.c

@@ -197,6 +197,7 @@ static void packet_queue_flush(PacketQueue *q)
     for(pkt = q->first_pkt; pkt != NULL; pkt = pkt1) {
         pkt1 = pkt->next;
         av_free_packet(&pkt->pkt);
+        av_freep(&pkt);
     }
     q->last_pkt = NULL;
     q->first_pkt = NULL;