'Restore volume from backup.
For a full list of available parameters, please refer to the official
API reference:
http://developer.openstack.org/api-ref/block-storage/v2/#restore-backup'

def restore_backup(self, backup_id, **kwargs):

    post_body = json.dumps({'restore': kwargs})
    (resp, body) = self.post(('backups/%s/restore' % backup_id), post_body)
    body = json.loads(body)
    self.expected_success(202, resp.status)
    return rest_client.ResponseBody(resp, body)
