Gerrit change 188848 takes advantage of the feature added to luasandbox in Gerrit change 84985, however the unit tests are failing because Jenkins is using an outdated version of php-luasandbox. Jenkins must use precise when running the zend unit tests as long as MediaWiki still supports PHP 5.3, since trusty comes with PHP 5.5.
Please upgrade php-luasandbox in the Wikimedia precise repo to a newer version. Thanks.