Avoid a nil index crash

Kyle

2013-02-22 985401a23d1581e71f762bdaeadfc19734fdf148

 technic/alloy_furnace.lua

@@ -198,6 +198,9 @@
return nil
end

register_LV_machine ("technic:alloy_furnace","RE")
register_LV_machine ("technic:alloy_furnace_active","RE")

--coal driven alloy furnace:

coal_alloy_furnace_formspec =