use addClassResourceCleanup in test_roles

Replaces resource_cleanup with addClassResourceCleanup in
test_roles.

test_utils.call_and_ignore_notfound_exc is NOT used in resource_setup
as delete_role_from_user_on_project and similar calls, do not delete
the role, it just unassigns the role from the target.

Change-Id: I5930c5f9d68b0258620e6de90398b34f84e06d9f
1 file changed