log when feed is already being received

Originally committed as revision 13939 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffserver.c

@@ -1341,6 +1341,7 @@ static int http_parse_request(HTTPContext *c)
     /* If already streaming this feed, do not let start another feeder. */
     if (stream->feed_opened) {
         snprintf(msg, sizeof(msg), "This feed is already being received.");
+        http_log("feed %s already being received\n", stream->feed_filename);
         goto send_error;
     }