Zlaves don't make a whole lot of sense. Somehow, with a little bit of
first aid knowledge, you can completely disable all functions of a
zombie.
A more sensible implementation of zlaves would have ones that can only
physically attack trying to bump into you, and and any ones that can
special attack still be able to do that.
Past all that, they would at least slowly regain lost function, much
like they revive.
This makes them effectively useless, so let's skip that work, and just
cut them out.