Fix broken maintenance mode
Fix broken maintenance mode

Maintenance mode has been broken since r7fe19ebfe0d3 (Thu Jun 4)
"Display caught errors on the page itself", fix it by passing the
site entity, rather than the site module to isActivePeriod.

MatthewWilkes/mw4068-packaging,MatthewWilkes/mw4068-packaging,MatthewWilkes/mw4068-packaging,MatthewWilkes/mw4068-packaging