remove unused lua code

this lua codes weren't used, on the other hand they break modifications that could be used with LoW otherwise.

data/campaigns/Legend_of_Wesmere/scenarios/chapter1/03_Kalian_under_Attack.cfg

@@ -55,15 +55,7 @@
             first_time_only=no
             [lua]
                 code = <<
-				H = wesnoth.require "lua/helper.lua"
-				W = H.set_wml_action_metatable {}
-				_ = wesnoth.textdomain "my-campaign"
-
-				-- Define your global constants here.
-				-- ...
 				ai = {}
-				ca_counter = 0
-				H.set_wml_var_metatable(_G)
 			>>
             [/lua]
         [/event]