Fixes second part of #6145

Fixes second part of #6145

Food in containers rots, because `item::fridge` is only set for the container, not for the content, fixed herby.

Item not getting cool is caused by the item_counter, which is unsigned and gets decremented by 10 in the fridge. The code that handles cool down process_active_item decrements it further and than checks it against 0. In 9 of 10 cases the decrementing leads to an overflow and item_counter is now very big (and not even near 0). And the whole cycle starts again.