Fixed compile time error.

code/modules/mob/living/carbon/human/human.dm

@@ -22,7 +22,7 @@
 	var/s_tone = 0.0
 	var/age = 30.0
 	var/used_skillpoints = 0
-	var/skills = null
+	var/list/skills = null
 //	var/b_type
 
 	var/obj/item/clothing/suit/wear_suit = null
@@ -2642,4 +2642,4 @@ It can still be worn/put on as normal.
 
 /mob/living/carbon/human/proc/check_dna()
 	dna.check_integrity(src)
-	return
+	return