Mark domain-config API as experimental in Identity spec

[Henry Nash]

Since the domain-config API is very recent, it makes sense to mark it as experimental. Further, our goal of migrating away from the concept of extension includes the support of marking individual APIs as experimental, deprecated etc. - however, we do not describe how a user of the API can discover this.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/162484

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/162484
Committed: https://git.openstack.org/cgit/openstack/keystone-specs/commit/?id=c30458fba68d86e91d269dcfde1fd004d07a7776
Submitter: Jenkins
Branch: master

commit c30458fba68d86e91d269dcfde1fd004d07a7776
Author: Henry Nash <email address hidden>
Date: Sun Mar 8 17:51:05 2015 +0000

    Mark the domain-config API as experimental

    We should consider the domain-config resouces and APIs as
    experimental, so as well as indicating this is the spec, we should
    describe how a caller can determine this via the API.

    Change-Id: I112aff129aceef506aead28379e81034fd41d4c6
    Closes-bug: 1429557