[PATCH] Animals should abandon chase if their target is too far

[mimo]

When you attack an dangerous animal, and then retreat, this animal will always chase you even if you flee to the opposite side of the map, completely out of its vision. There is a comment in the ShouldAbandonChase method saying that CCmpUnitMotion should take care to stop it if the target is lost in FoW, but this does not seem to work with animals. So here is a simple patch which stops the chase if the target is too far from the animal which chase it.