Fixes organs not being removed due to damage

Because the dismemberment check was being done before brute_dam was
updated, the attack that actually brought brute_dam above the threshold
would not be able to pass the check, regardless of how much damage was
actually done.
Fixes suits being punctured by projectiles when...

...fully blocked by a shield.
Fixes melee attacks using area effect armour values

def_zone is normally not set when attacking with a melee weapon, and the
melee armour check didn't use target_zone for some reason.