Rackspace CDN is global but is associated with a region #24
Description
With Rackspace CDN, the endpoint for the service is global. However in the service catalog, it is associated with the DFW region. This means that users must know this quirk and specify DFW when using the CDN service with Rackspace. It would be preferable if the SDK would deal with it instead.
Copied from openstacknetsdk/openstack.net#525