Runtime fix for building AIs without a brain

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@5504 316c924e-a436-60f5-8080-3fe189b3f50e

code/game/machinery/computer/ai_core.dm

@@ -155,7 +155,8 @@
 				playsound(loc, 'sound/items/Screwdriver.ogg', 50, 1)
 				user << "\blue You connect the monitor."
 				var/mob/living/silicon/ai/A = new /mob/living/silicon/ai ( loc, laws, brain )
-				A.rename_self("ai", 1)
+				if(A) //if there's no brain, the mob is deleted and a structure/AIcore is created
+					A.rename_self("ai", 1)
 				feedback_inc("cyborg_ais_created",1)
 				del(src)