Borer fixes

- Fixes borers dying to environmental damage while inside a host.
- Fixes borers not releasing control of a host when it dies.
- Fixes borers being able to assume control of dead hosts.
- Fixes borers being able to talk to their host while dead.
- Fixes borers being told they can't leave their host while
incapacitated/dead, but then trying to leave it anyway.
- Removes an unused proc.

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

@@ -111,7 +111,7 @@
 			if(istype(I,/mob/living/simple_animal/borer))
 				B = I
 	if(B)
-		if(!B.ckey && ckey && B.controlling)
+		if(B.controlling && B.host == src)
 			B.detatch()
 
 		verbs -= /mob/living/carbon/proc/release_control