Adds defines for organ slots

code/modules/zombie/items.dm

@@ -44,7 +44,7 @@
 		return
 
 	var/obj/item/organ/zombie_infection/infection
-	infection = target.getorganslot("zombie_infection")
+	infection = target.getorganslot(ORGAN_SLOT_ZOMBIE)
 	if(!infection)
 		infection = new()
 		infection.Insert(target)

code/modules/zombie/organs.dm

@@ -2,7 +2,7 @@
 	name = "festering ooze"
 	desc = "A black web of pus and viscera."
 	zone = "head"
-	slot = "zombie_infection"
+	slot = ORGAN_SLOT_ZOMBIE
 	icon_state = "blacktumor"
 	origin_tech = "biotech=5"
 	var/datum/species/old_species = /datum/species/human