Add edge case tests for disabling a trustee
Add edge case tests for disabling a trustee

This commit introduces two tests that ensures if a trustee of a
trust-scoped token is disabled, keystone will emit a Forbidden
exception. Regardless of the token provider, keystone should have
a consistent behavior. In order to test this, the test had to be
implemented differently for each token provider, specifically for
persistent and non-persistent tokens.

Co-Authored-By: Lance Bragstad <c07efdf7ead33de21c0f28854ad0a94dbdcbb98d@gmail.com>
Change-Id: Iaf04a26c9f60eb68bbd56b941ff76c893c144cb8

mahak/keystone,ilay09/keystone,ilay09/keystone,openstack/keystone,rajalokan/keystone,rajalokan/keystone,mahak/keystone,openstack/keystone,mahak/keystone,openstack/keystone,rajalokan/keystone,ilay09/keystone