error when newSocket is undefined in lib/_http_agent.js

[k1tzu]

in https://github.com/nodejs/node/blob/master/lib/_http_agent.js
you have the code

const newSocket = self.createConnection(options, oncreate);
...
function oncreate(err, s) {
...
if (err)
      return cb(err); 
... 
}

//cb returns us to to
this.createSocket(req, options, function(err, newSocket) {
      if (err) {
        nextTick(newSocket._handle.getAsyncId(), function() {
          req.emit('error', err);
        });
...

How can you call _handle on newSocket in case there was an error creating that newSocket?
Looks not right to me.

For example where I run into it:
I have a need in a simple custom .createConnection where I do

    this.createConnection = (options, callback) => {
    let localhandle = net._createServerHandle(options.localAddress);
    if (typeof localhandle === 'number') {
        return callback("handle creation error: "+localhandle);
    }
...

And since one of your latest releases I'm receiving this error from time to time when localhandle is an error:

TypeError: Cannot read property '_handle' of undefined
                                              at _http_agent.js:186:27
                                              at oncreate (_http_agent.js:230:14)

[mscdex]

This is a duplicate of the second part of this issue which I've now re-opened.