add memory leak fix

Reference: http-party/node-http-proxy#1510

lib/http-proxy/passes/ws-incoming.js

@@ -129,7 +129,7 @@ module.exports = {
       // if it errors (eg, vanishes from the net and starts returning
       // EHOSTUNREACH). We need to do that explicitly.
       socket.on('error', function () {
-        proxySocket.end();
+        proxySocket.destroy();
       });
 
       common.setupSocket(proxySocket);