Fix remaining non-returning Destroys()

Plus a little refactor to mining flaps and spacepod doors- they now use
CanAtmosPass instead of manually setting the turf to no-atmos-passing

code/modules/assembly/assembly.dm

@@ -70,8 +70,8 @@
 			else if(A.a_right == src)
 				A.a_right = null
 			src.holder = null
-		..()
-			
+		return ..()
+
 	pulsed(var/radio = 0)
 		if(holder && (wires & WIRE_RECEIVE))
 			activate()

code/modules/assembly/holder.dm

@@ -29,7 +29,7 @@
 			a_left.holder = null
 		if(a_right)
 			a_right.holder = null
-		..()
+		return ..()
 
 	attach(var/obj/item/device/D, var/obj/item/device/D2, var/mob/user)
 		if((!D)||(!D2))	return 0