Workaround for drupal.org update realted drush make bug

Drush make fails to download Drupal core 7.23 after site-wide
upgrade of drupal.org. The related upstream bug could be found
here: https://github.com/drush-ops/drush/issues/234

Change-Id: Ieb0a818518ab7ef3f68a5c00b462836a5074a395
Related-Bug: #1247925