Fix the site_url in config.js

[slopjong]

<ms7821> anyone knwo who's responsible for https://spaceapi.net/config.js
<ms7821> any chance they could fix https://spaceapi.net/validator by changing site_url to just '//spaceapi.net'?
<ZombiePoet> Title: The Space API (at spaceapi.net)
<ms7821> (currently it fails kinda badly but non-obviously if you visit the address over https)
<ms7821> (might also be worth adding a .fail() to any $.getJSON calls, but changing the config is a quick win)

Quickfix applied on the production server directly. Not yet in VCS.