Before, we needed to unset a couple of parameters that would make the
client return a project-scoped token instead of a system-scoped token,
which we need when interacting with registered limits in keystone.
This commit removes those unsets since we no longer source those
variables by default. This commit also cleans up some of the redundant
parameters in the registered limit calls, like region.
Change-Id: I1af8a168a29e895d57504d41e30efea271ea232d
afd0f84eae