'Delete a role.
For a full list of available parameters, please refer to the official
API reference:
https://developer.openstack.org/api-ref/identity/v2-ext/index.html#delete-a-role'

def delete_role(self, role_id):

    (resp, body) = self.delete(('OS-KSADM/roles/%s' % role_id))
    self.expected_success(204, resp.status)
    return rest_client.ResponseBody(resp, body)
