'Unmanage a snapshot.'

def unmanage_snapshot(self, snapshot_id):

    post_body = json.dumps({'os-unmanage': {}})
    url = ('snapshots/%s/action' % snapshot_id)
    (resp, body) = self.post(url, post_body)
    self.expected_success(202, resp.status)
    return rest_client.ResponseBody(resp, body)
