Introduction to "target.token.*" is needed in the RBAC part of configuration.rst

[DWang]

When limiting access to token-related operations, we may need references like %(target.token.user.domain.id)s.

However possible values of "target.token.*" is missing while "target.user.*", "target.role.*" and so on are listed in configuration.rst:

http://docs.openstack.org/developer/keystone/configuration.html#keystone-api-protection-with-role-based-access-control-rbac

I think this work will supplement keystone's current documentation.

[DWang (darren-wang)]

I don't know why but I can't open Keystone Dev Docs for a while, is the server down?

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/182147

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/182147
Committed: https://git.openstack.org/cgit/openstack/keystone/commit/?id=67ec368ac1ad24eb1b5921a2d20066df9053337e
Submitter: Jenkins
Branch: master

commit 67ec368ac1ad24eb1b5921a2d20066df9053337e
Author: Dave Chen <email address hidden>
Date: Tue May 12 11:37:53 2015 +0800

    Add missing part for `token` object

    Provide some attributes for token which can also be used
    in policy language.

    Change-Id: Ib09a1765e43502ca9c5d00641b85ab70988bc564
    Closes-Bug: #1448991