Refactored the locking options + JRuby compatibilities

1) "sleep 1.second" doesn't work with JRuby. Workaround with "sleep 1.second.to_f"
2) Removed the try_lock method in Redis::Mutex, we don't use it.
3) Removed the whole locking logic in the publisher bootstrap data code, it's useless:
   The subscriber only cares if the document is newer than the bootstrap time.