The server method returns `self` in order to allow chaining.
PR-URL: https://github.com/nodejs/node/pull/4590
Fixes: https://github.com/nodejs/node/issues/4571
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>
This function is asynchronous. The last parameter `callback` will be added as
a listener for the `'listening'` event. See also [`net.Server.listen()`][].
+Returns `server`.
+
### server.listen(path[, callback])
Start a UNIX socket server listening for connections on the given `path`.