remove unused queues

- search_sync is staying around for now, because of how job uniqueness
is implemented
- seems like a good idea to also keep ‘default’ around even though no
worker/job uses it.  It is the default queue that sidekiq uses. So just
a smart move to keep it around?
- remove all other unused queues
Merge pull request #252 from codebender/remove_old_sidekiq_queues

remove unused queues