Don't use beanstalk client directly, subclass custodian/queue, or similar
to allow us to swap out the queue and stub it for testing.

Use a class factory to instantiate tests on the worker-side.
-> This is in-progress.  Test it with:
     ./bin/custodian-parse-execute "kvm1.vm must run smtp."

The HTTP/HTTPS-probe should be pure Ruby.  Patrick will give me a stub.