Use cloud access URL to generate CPID.
Use cloud access URL to generate CPID.

This spec proposes RefStack to add a method to use the cloud access URL
as the base to generate the CPID.

Change-Id: I118a77f4cb328908a528376a038a43684427dbfa

stackforge/refstack,openstack/refstack,openstack/refstack,openstack/refstack,stackforge/refstack,openstack/refstack,stackforge/refstack,stackforge/refstack