Expires comparison raises TypeError in middleware.auth_token

[Tiantian Gao]

The method '_cache_put' set the Expires to float, but when _cache_get get the Expires ,it can't compare a float and a datetime.
-----------------------
 if expires <= datetime.now():
TypeError: can't compare datetime.datetime to float

[Ziad Sawalha (ziad-sawalha)]

Should be addressed by https://review.openstack.org/3185

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/3185
Committed: http://github.com/openstack/keystone/commit/8c98285ad0c1b24efe35a3ea777da58fb0d67054
Submitter: Jenkins
Branch: master

commit 8c98285ad0c1b24efe35a3ea777da58fb0d67054
Author: Ziad Sawalha <email address hidden>
Date: Thu Jan 19 11:19:13 2012 -0600

    Fixes 918535: time not properly parsed in auth_token middleware

    - replaced get_datetime() with expanded _convert_datetime()
      function that uses datutil parser to handle any date
      string.
    - added tests
    - fixes bug 918535
    - also addresses bug 911197

    Change-Id: I7f4e3c01b1b7466fd5f30889c7b28deae9fc9367