Cleanup duplicate call (#522)

Luke aka SwissalpS

2019-12-25 76a39e71b9f81531e14efd7ec1b0accfefa0fa66

 technic/machines/other/injector.lua

@@ -95,7 +95,7 @@
         if meta:get_int("splitstacks") == 1 then
            stack = stack:peek_item(1)
         end
         return meta:get_inventory():room_for_item("main", stack)
         return inv:room_for_item("main", stack)
      end,
      insert_object = function(pos, node, stack, direction)
         return minetest.get_meta(pos):get_inventory():add_item("main", stack)