Allow bin/aphlict to start without a valid database connection

Summary:
Ref T11818. See that task for a description.

This is like a tiny pinch of hackiness but not really unreasonable. Basically, aphlict is already an "uber-server" and one copy can handle a ton of instances.

Test Plan: Started bin/aphlict without a valid database connection.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11818

Differential Revision: https://secure.phabricator.com/D16854