dgram: remove stale code

lib/dgram.js

@@ -209,10 +209,6 @@ Socket.prototype.send = function(buffer,
 function afterSend(status, handle, req, buffer) {
   var self = handle.owner;
 
-  // CHECKME socket's been closed by user, don't call callback?
-  if (handle !== self._handle)
-    void(0);
-
   if (req.cb)
     req.cb(null, buffer.length); // compatibility with dgram_legacy.js
 }
@@ -320,11 +316,6 @@ Socket.prototype._stopReceiving = function() {
   if (!this._receiving)
     return;
 
-  // Black hole messages coming in when reading is stopped. Libuv might do
-  // this, but node applications (e.g. test/simple/test-dgram-pingpong) may
-  // not expect it.
-  this._handle.onmessage = noop;
-
   this._handle.recvStop();
   this._receiving = false;
   this.fd = null; // compatibility hack