Add support for specifying custom domains

Add the ability to pass user_domain_id / user_domain_name, domain_id
/ domain_name, and project_domain_id / project_domain_name to keystone.
These parameters are the first step needed to getting multi-domain
support working via the CLI.

Closes-Bug: #1198171
Change-Id: I81a8534913978ff1cce01ec02741ae477e8c5fa4
Signed-off-by: Paul Belanger <paul.belanger@polybeacon.com>
Signed-off-by: Bo Tang <btang@cs.utsa.edu>
Merge "Add support for specifying custom domains"