Inject _design/_auth on auth_cache startup
Inject _design/_auth on auth_cache startup

We send start_listener event from init to make sure we call
ensure_auth_ddoc_exists as soon as we can. Rather then calling it on
listener restart.

COUCHDB-3000

fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb