Fix test errors.

Still some failures to be addressed anon.
Fix expectation hooks that get lost.

scheduler_test.rb#test_enqueue_runs_hooks sets expectations that Resque
hooks are run. These are lost with the Resque::Plugin hook memoization
changes unless the methods are concrete.
Namespace keys in scripted redis actions.

Resque 2.x wraps the redis instances in redis-namespace.
Resque-scheduler has two methods that bypass the namespace:
* Resque::Scheduler::Lock::Resilient#acquire!
* Resque::Scheduler::Lock::Resilient#locked?