http: use `localAddress` instead of `path`

Fix `options` usage on `lib/_http_agent.js` for the Legacy API.

Fixes: https://github.com/nodejs/node/issues/5051
PR-URL: https://github.com/nodejs/node/pull/5190


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: James M Snell <jasnell@gmail.com>