Fixed "Invalid argument to getAgent" when proxying HTTP

lib/node-http-proxy.js

@@ -45,10 +45,8 @@ exports.version = [0, 5, 0];
 // and sets the `maxSockets` property appropriately.
 //
 function _getAgent (host, port, secure) {
-  var agent = !secure ? http.getAgent(host, port) : https.getAgent({ 
-    host: host, 
-    port: port 
-  });
+  var options = { host: host, port: port };
+  var agent = !secure ? http.getAgent(options) : https.getAgent(options);
 
   agent.maxSockets = maxSockets;
   return agent;