Trust execution fails when trustor is in LDAP

[Adam Young]

the token provider code is checking the enabled attribute on the when excuting a trust. However, in many LDAP deployments, this value is unset, and

For the auth plugins, the enabled logic is calculated in identity/core.py. THe token provider should use this code as well.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/120592

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/120592
Committed: https://git.openstack.org/cgit/openstack/keystone/commit/?id=948d51025fb7759d2f1267e0c25edd8832495b1c
Submitter: Jenkins
Branch: master

commit 948d51025fb7759d2f1267e0c25edd8832495b1c
Author: Adam Young <email address hidden>
Date: Wed Sep 10 21:37:27 2014 +0000

    Safer check for enabled in trusts

    For some LDAP backends, the enable attribute is not
    directly set. Since we have a wrapper function in identity/core,
    we can use that instead.

    Adds tests that disabling trustor or trustee prevents
    trust execution.

    Closes-Bug: 1367952

    Change-Id: I6d3c26e0e6e6c0d27ea7b910340fae5792eaceda