Lua AIs: remove inclusions of unused libraries

(cherry-picked from commit 8a996c55b9)

data/ai/lua/generic_recruit_engine.lua

@@ -24,7 +24,6 @@ return {
         math.randomseed(os.time())
 
         local AH = wesnoth.require "ai/lua/ai_helper.lua"
-        local LS = wesnoth.require "location_set"
         local M = wesnoth.map
 
         local function print_time(...)

data/ai/lua/generic_rush_engine.lua

@@ -8,7 +8,6 @@ return {
 
         local AH = wesnoth.require "ai/lua/ai_helper.lua"
         local BC = wesnoth.require "ai/lua/battle_calcs.lua"
-        local LS = wesnoth.require "location_set"
         local HS = wesnoth.require "ai/micro_ais/cas/ca_healer_move.lua"
         local R = wesnoth.require "ai/lua/retreat.lua"
         local M = wesnoth.map

data/ai/micro_ais/cas/ca_forest_animals_move.lua

@@ -1,7 +1,6 @@
 local AH = wesnoth.require "ai/lua/ai_helper.lua"
 local LS = wesnoth.require "location_set"
 local M = wesnoth.map
-local T = wml.tag
 
 local function get_forest_animals(cfg)
     -- We want the deer/rabbits to move first, tuskers afterward

data/ai/micro_ais/cas/ca_forest_animals_new_rabbit.lua

@@ -1,5 +1,4 @@
 local AH = wesnoth.require "ai/lua/ai_helper.lua"
-local T = wml.tag
 
 local ca_forest_animals_new_rabbit = {}