avplay: free the active audio packet at exit.

fixes a memleak

avplay.c

@@ -2268,6 +2268,7 @@ static void stream_component_close(VideoState *is, int stream_index)
         SDL_CloseAudio();
 
         packet_queue_end(&is->audioq);
+        av_free_packet(&is->audio_pkt);
         if (is->reformat_ctx)
             av_audio_convert_free(is->reformat_ctx);
         is->reformat_ctx = NULL;