ws client: Don't include offers with 'completed' event

It's not necessary to include webrtc offers because the client is not
really looking for more peers when it has just completed the torrent.

Fewer WebRTC offers = less resource usage

Author: feross

lib/client/websocket-tracker.js

@@ -60,8 +60,8 @@ WebSocketTracker.prototype.announce = function (opts) {
   })
   if (self._trackerId) params.trackerid = self._trackerId
 
-  if (opts.event === 'stopped') {
-    // Don't include offers with 'stopped' event
+  if (opts.event === 'stopped' || opts.event === 'completed') {
+    // Don't include offers with 'stopped' or 'completed' event
     self._send(params)
   } else {
     // Limit the number of offers that are generated, since it can be slow