We're trying to get things to use volume v2 by default. devstack already
deploys a v2 endpoint. Tell clouds.yaml that this devstack cloud is a v2
enabled cloud.
Change-Id: I6f792ce65153389aa1ee133e9bd363c394b28534
Closes-Bug: 1467589
When using IDENTITY_API_VERSION=3, the clouds.yaml must also set
auth/user_domain_id and project_domain_id.
Change-Id: If028f2935ea729276f40039a4003c07c08e91672