'Updates a user.
For a full list of available parameters, please refer to the official
API reference:
http://developer.openstack.org/api-ref/identity/v3/#update-user'

def update_user(self, user_id, **kwargs):

    if ('id' not in kwargs):
        kwargs['id'] = user_id
    post_body = json.dumps({'user': kwargs})
    (resp, body) = self.patch(('users/%s' % user_id), post_body)
    self.expected_success(200, resp.status)
    body = json.loads(body)
    return rest_client.ResponseBody(resp, body)
