The Most Obvious Way to Get a Service Catalog That You Have to See to Believe

This introduces a new call for authenticated users to retrieve a service
catalog from Keystone. It is designed to compliment tokens generated
using ?nocatalog.

blueprint: get-catalog
Change-Id: Ia967032839c5575c72a6459974114a0165921cc9
Merge "The Most Obvious Way to Get a Service Catalog That You Have to See to Believe"