Fix default values for NullEngine as per method contract.
Fix default values for NullEngine as per method contract.

cakephp/cakephp,cakephp/cakephp,cakephp/cakephp,ndm2/cakephp,ADmad/cakephp,dakota/cakephp,ndm2/cakephp,ndm2/cakephp,CakeDC/cakephp,CakeDC/cakephp,CakeDC/cakephp,ADmad/cakephp,CakeDC/cakephp,ADmad/cakephp,dakota/cakephp,dakota/cakephp,cakephp/cakephp,ndm2/cakephp,dakota/cakephp,ADmad/cakephp