Automatically select the right Conduit URI path for the irc bot

Summary: The docs say "http://www.domain.com/" but if you don't put "/api/" it fails. GOTCHA!

Test Plan: Removed "/api/", launched bot, it worked.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran, epriestley

Maniphest Tasks: T935

Differential Revision: https://secure.phabricator.com/D1763