Fixes borers and antag spawning. (#7917)

Fixed bughunt for real.
    Bughunt now tries to spawn four mercenaries and two borers.
    Added some more intro text to Renegade.

code/modules/organs/internal/brain.dm

@@ -166,7 +166,7 @@
 
 /obj/item/organ/internal/brain/proc/brain_damage_callback(var/damage) //Confuse them as a somewhat uncommon aftershock. Side note: Only here so a spawn isn't used. Also, for the sake of a unique timer.
 	to_chat(owner, "<span class = 'notice' font size='10'><B>I can't remember which way is forward...</B></span>")
-	owner.confused += damage
+	owner?.confused += damage
 
 /obj/item/organ/internal/brain/proc/handle_severe_brain_damage()
 	set waitfor = FALSE

code/modules/organs/misc.dm

@@ -1,5 +1,5 @@
 // This borer is the worm that replaced the host's brain, not the brainworm latched onto a brain
-/obj/item/organ/borer
+/obj/item/organ/internal/borer
 	name = "cortical borer"
 	icon = 'icons/obj/objects.dmi'
 	icon_state = "borer"
@@ -8,7 +8,7 @@
 	parent_organ = BP_HEAD
 	vital = TRUE
 
-/obj/item/organ/borer/removed(var/mob/living/user)
+/obj/item/organ/internal/borer/removed(var/mob/living/user)
 	..()
 
 	var/mob/living/simple_animal/borer/B = owner.has_brain_worms()