Resolves an issue with commit https://github.com/tgstation/-tg-station/commit/f3996dfc5e64408ec95f9b43fe05df348af5978c

... doing the opposite of what it was supposed to.

Mobs can now become bloody again...after 9 months of going unnoticed.

Credits to Mport for this fix <3

Modified   code/modules/mob/living/carbon/human/human_defense.dm

Signed-off-by: carnie <elly1989@rocketmail.com>