'Delete a namespace.
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#delete-namespace'

def delete_namespace(self, namespace):

    url = ('metadefs/namespaces/%s' % namespace)
    (resp, _) = self.delete(url)
    self.expected_success(204, resp.status)
    return rest_client.ResponseBody(resp)
