Fix GH-819. Drop out if connection destroyed before connect()

lib/net.js

@@ -547,6 +547,8 @@ Socket.prototype.setEncoding = function(encoding) {
 
 
 function doConnect(socket, port, host) {
+  if (socket.destroyed) return;
+
   timers.active(socket);
 
   try {

test/simple/test-regress-GH-819.js

@@ -0,0 +1,7 @@
+var common = require('../common');
+var net = require('net');
+var assert = require('assert');
+
+// Connect to something that we need to DNS resolve
+var c = net.createConnection(80, "google.com");
+c.destroy();