Clearer registraton LWRP tests

This is a much clearer way to test LWRPs are executed with
the proper options.  The previous approach was hacky, and
relied upon too much stubbing and ruby magik.  Also, updated
to berkshelf 2.0 where Berksfile.lock is respected.  This
is necessary for berkshelf to lock to the proper cookbook
deps in openstack's CI system.

Change-Id: I21c1c000581f2d3c94ff2f9628f0cea0f6536013