Player's pet killed a troll with Trollsbane and the corpse later
revived. He assumed that killing a troll with Trollsbane is what
prevents troll corpse revival but that is inhibited by the hero
be wielding Trollsbane at the time revival is attempted.
Having killed-by-Trollsbane be the reason for blocking revival
would be much better but looks like a lot of work for something
which was supposed to be a one-line enhancement to an under-used
artifact. This extends revival inhibition to having anyone on
the level be wielding Trollsbane rather than just the hero.
Not a proper fix but I think it's better than nothing.
Closes#475
3cd45b7c44