"Set" and then "get" don't retrieve the stored value

[Jehiah Czebotar]

> > Wish I had a clever way of solving the base problem though.  Alas, I
> > don't.  :)
> We could do gross stuff like using the lower (always zero) bits of various
> pointers in item* for the world generation number, but I think the CPU
> cost of maintain those wouldn't be worth it.

I think this is a simpler fix; instead of marking the item as deleted
with the current timestamp; mark it deleted with a timestamp in the
past

change
it->exptime = realtime(exptime);
to
it->exptime = realtime(exptime)-1;

--
Jehiah