While I don't mind moving the global check into get_lock, I don't like moving this into the arguments of get_lock, unless we're not planning on writing more eqc tests for it. Having a function in bg-mgr that does the checks for you is cool, though. Otherwise, it's going to get messy. We'd need to add these to more of the API, at least get_token, and set_concurrency_limit. More surface area.

I propose that I create two additional helper functions in bg-mgr that do the config checking, but the call points still do the tests.