This fixes the reported situation of recoiling from a throw while
levitating and carrying the ball not bringing the chain but it might
introduce other problems. If it does, drag_ball() would be the place
to fix that, not hurtle_step().
Separate bug (not fixed): throwing while the ball is on the floor
ought to let you recoil to as far as the chain will reach but it just
yields "you feel a tug from the ball" and you don't recoil at all.
8ccc9773aa