Fixing Anubis

I finally tracked down (hopefully) the last of my Anubis issues: A stray 503 on the first page load after passing PoW check.

Before giving in and resorting to Anubis, I was trying to rate-limit directly in nginx. I have no clue how this would turn into a 503, but disabling a stray limit directive that survived the transition seems to have fixed the problem.