EphemeralSocket should be exclusive

... otherwise it doesn't play nicely with cluster. 

Similar: nodejs/node-v0.x-archive#8643

Author: jbt

lib/EphemeralSocket.js

@@ -117,7 +117,7 @@ EphemeralSocket.prototype._createSocket = function (callback) {
     this._socket.once('listening', function () {
         return callback();
     });
-    this._socket.bind(0, null);
+    this._socket.bind({ port: 0, exclusive: true }, null);
 
     // Start timer, if we have a positive timeout
     if (this._socketTimeoutMsec > 0 && !this._socketTimer) {