added 'mask' option hint to file cache docblock
added 'mask' option hint to file cache docblock


	See: cakephp/cakephp@bc8feefc89d54b23a005f8a3f29f7b6c5d987390


makallio85/fish-diary,ojengwa/cake-appengine,QoboLtd/project-template-cakephp,ojengwa/cake-appengine,makallio85/fish-diary,QoboLtd/project-template-cakephp,QoboLtd/project-template-cakephp,makallio85/fish-diary,QoboLtd/project-template-cakephp,QoboLtd/project-template-cakephp