[fix] Don't remove error listener after response ends

In some rare cases, `error` event might still be emitted after the
response has ended. This is (most likely) a bug in the `node` core.

Author: mmalecki

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

@@ -271,8 +271,6 @@ HttpProxy.prototype.proxyRequest = function (req, res, buffer) {
     response.on('end', function () {
       ended = true;
       if (!errState) {
-        reverseProxy.removeListener('error', proxyError);
-
         try { res.end() }
         catch (ex) { console.error("res.end error: %s", ex.message) }