Default to PKI tokens

[Adam Young]

Currently the default is UUID tokens. Switch this to PKI tokens.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/14167

[Boden R (boden)]

If PKI is used by default, will we ship a 'default' set of certs or will we update the docs to inform the user that PKI is the default and they need to generate the appropriate cert artifacts?

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/14167
Committed: http://github.com/openstack/keystone/commit/cb122095cfdbe86bdde3950fa69f4676e0d3de1c
Submitter: Jenkins
Branch: master

commit cb122095cfdbe86bdde3950fa69f4676e0d3de1c
Author: Adam Young <email address hidden>
Date: Mon Oct 8 11:20:24 2012 -0400

    Fixes Bug 1063852

    Add in the issue time, to prevent a race condition where a token is issued and
    revoked, and then a request for an additional token is processed identical
    to the first. Each token now contains the issue time to make it unique.

    (moving changing default to PKI to separate review)

    Change-Id: I26ed5b3bb31840f5baaf64dbcbeac477e4d71afd