Comment 17 for bug 1582585

Thanks for the patches Billy. I've reviewed the patches and I think they justify an SRU.

Some notes from my review:
* Patches 1 through 3 are fairly straight forward cherry-picks that are already in Newton and require a very minimal changes to apply to Mitaka.
* Patch 3 adds a new 'mapping_populate' subcommand to keystone-manage that enables creation of id mapping entries. This is a feature, and while we typically don't backport features, I think this case is warranted as it is an optional command that allows an admin to pre-create pubic IDs to prevent users from hitting costly CLI/API calls.
* Patch requires additional code to handle backends that don't support get_domain_mapping_list(). I want to make sure testing of the fallback path is performed in addition to the new path.

To avoid regression of existing consumers, the OpenStack team will run their continuous integration tests against the packages that are in -proposed.