[refactor] Updates to support http2 from @mikeal

Conflicts:

	lib/node-http-proxy/http-proxy.js

lib/node-http-proxy/http-proxy.js

@@ -25,6 +25,7 @@
 */
 
 var events = require('events'),
+    http = require('http'),
     util = require('util'),
     httpProxy = require('../node-http-proxy');
 
@@ -594,6 +595,7 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
   outgoing.method  = 'GET';
   outgoing.path    = req.url;
   outgoing.headers = req.headers;
+  outgoing.agent   = agent;
 
   var reverseProxy = this.target.protocol.request(outgoing);
 
@@ -617,7 +619,6 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
   // available to the `upgrade` event. This bookkeeping is not tracked anywhere
   // in nodejs core and is **very** specific to proxying WebSockets.
   //
-  reverseProxy.agent = agent;
   reverseProxy.incoming = {
     request: req,
     socket: socket,
@@ -632,17 +633,15 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
   // In addition, it's important to note the closure scope here. Since
   // there is no mapping of the socket to the request bound to it.
   //
-  if (!agent._events || agent._events['upgrade'].length === 0) {
-    agent.on('upgrade', function (_, remoteSocket, head) {
-      //
-      // Prepare the socket for the reverseProxy request and begin to
-      // stream data between the two sockets. Here it is important to
-      // note that `remoteSocket._httpMessage === reverseProxy`.
-      //
-      _socket(remoteSocket, true);
-      onUpgrade(remoteSocket._httpMessage, remoteSocket);
-    });
-  }
+  reverseProxy.on('upgrade', function (_, remoteSocket, head) {
+    //
+    // Prepare the socket for the reverseProxy request and begin to
+    // stream data between the two sockets. Here it is important to
+    // note that `remoteSocket._httpMessage === reverseProxy`.
+    //
+    _socket(remoteSocket, true);
+    onUpgrade(remoteSocket._httpMessage, remoteSocket);
+  });
 
   //
   // If the reverseProxy connection has an underlying socket,