Set session save handler when the engine is swapped.
Set session save handler when the engine is swapped.

Refs #11895

davidyell/cakephp,tenkoma/cakephp,garethellis36/cakephp,tenkoma/cakephp,garethellis36/cakephp,CakeDC/cakephp,ADmad/cakephp,garethellis36/cakephp,dakota/cakephp,mvdriel/cakephp,ADmad/cakephp,cakephp/cakephp,ndm2/cakephp,CakeDC/cakephp,CakeDC/cakephp,tenkoma/cakephp,davidyell/cakephp,petteyg/cakephp,dakota/cakephp,ADmad/cakephp,cakephp/cakephp,ndm2/cakephp,cakephp/cakephp,mvdriel/cakephp,garethellis36/cakephp,ndm2/cakephp,CakeDC/cakephp,tenkoma/cakephp,petteyg/cakephp,mvdriel/cakephp,ADmad/cakephp,cakephp/cakephp,petteyg/cakephp,dakota/cakephp,mvdriel/cakephp,dakota/cakephp,davidyell/cakephp,ndm2/cakephp,petteyg/cakephp