Allow unlimited listeners on reverseProxy

reverseProxy can have many subscribers to the 'drain' event when large
uploads occur.

Author: jcheng5

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

@@ -354,6 +354,9 @@ HttpProxy.prototype.proxyRequest = function (req, res, buffer) {
     res.on('drain', ondrain);
   });
 
+  // There can be many subscribers to the 'drain' event during large uploads.
+  reverseProxy.setMaxListeners(0);
+
   //
   // Handle 'error' events from the `reverseProxy`. Setup timeout override if needed
   //