Fix typo in survival formspec & create legacy file

mods/default/functions.lua

@@ -83,25 +83,6 @@ function default.node_sound_glass_defaults(table)
 	return table
 end
 
---
--- Legacy
---
-
-function default.spawn_falling_node(p, nodename)
-	spawn_falling_node(p, nodename)
-end
-
--- Horrible crap to support old code
--- Don't use this and never do what this does, it's completely wrong!
--- (More specifically, the client and the C++ code doesn't get the group)
-function default.register_falling_node(nodename, texture)
-	minetest.log("error", debug.traceback())
-	minetest.log('error', "WARNING: default.register_falling_node is deprecated")
-	if minetest.registered_nodes[nodename] then
-		minetest.registered_nodes[nodename].groups.falling_node = 1
-	end
-end
-
 --
 -- Lavacooling
 --