Drupal 8 requires read permissions in sites/all

Otherwise it will yell with errors like this:
[23-Dec-2014 00:03:25 UTC] Uncaught PHP Exception UnexpectedValueException: "RecursiveDirectoryIterator::__construct(/var/aegir/platforms/drupal-8.0.0-beta4/sites/all): failed to open dir: Permission denied" at /var/aegir/platforms/drupal-8.0.0-beta4/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php line 339