Fix test_show_server_usage not checking expected attributes

While os_compute_api:os-server-usage policy in Nova is deprecated [0]
the current test in Patrole should be fixed since it is not
checking for expected attributes which are conditionally injected
following successful policy authorization. See [0] for details
on expected attributes.

[0] https://github.com/openstack/nova/blob/15f1caf98a46ba0ab3f8365075c564e89f06eef3/nova/policies/server_usage.py#L32

Change-Id: Ibc632cc084c2edb58c336f5ff56d2902bf2ccc96
1 file changed