added test case for when a queue is passed to 'enqueue_in_with_queue' wh...

I developed a proxy to abstract our code base from the background-processing library, which always calls the 'enqueue_in_with_queue' method.

The problem is that sometimes the queue name, it passes, is also defined inside the worker class (with an instance variable) and our specs are written like this "ResqueSpec.schedule_for(NameFromClassMethod).should_not be_empty". This causes our tests to break because the 'schedule_queue_name' always append '_scheduled' to the queue name. Removing this works fine for me and is not breaking any other test, so I suppose it's fine, since I also did not find any reference to it the resque_scheduler gem.