Reverted admin debug changes, nulled references after qdels

code/modules/library/computers/checkout.dm

@@ -198,6 +198,7 @@
 				dat += "<tr><td><A href='?src=\ref[src];manual=[manualcount]'>[M.title]</A></td></tr>"
 				manualcount++
 				qdel(M)
+				M = null
 			dat += "</table>"
 			dat += "<BR><A href='?src=\ref[src];switchscreen=0'>(Return to main menu)</A><BR>"
 

code/modules/library/lib_machines.dm

@@ -201,5 +201,6 @@ var/global/list/library_section_names = list("Any", "Fiction", "Non-Fiction", "A
 		b.name = "Print Job #[rand(100, 999)]"
 		b.icon_state = "book[rand(1,9)]"
 		qdel(O)
+		O = null
 	else
 		return ..()