'Update a namespace object
For a full list of available parameters, please refer to the official
API reference:
http://developer.openstack.org/api-ref/image/v2/metadefs-index.html#update-object'

def update_namespace_object(self, namespace, object_name, **kwargs):

    url = ('metadefs/namespaces/%s/objects/%s' % (namespace, object_name))
    data = json.dumps(kwargs)
    (resp, body) = self.put(url, data)
    self.expected_success(200, resp.status)
    body = json.loads(body)
    return rest_client.ResponseBody(resp, body)
