balance: allow to update qlx_balance* cvars between games

Before this commit, if new game starts with different values of
qlx_balanceUrl/Api/UseLocal, those values are ignored

Author: em92

balance.py

@@ -67,6 +67,10 @@ def __init__(self):
         self.set_cvar_once("qlx_balanceMinimumSuggestionDiff", "25")
         self.set_cvar_once("qlx_balanceApi", "elo")
 
+        self.cache_cvars()
+
+    def cache_cvars(self):
+        # Store some cvar values that are used in non-game threads
         self.use_local = self.get_cvar("qlx_balanceUseLocal", bool)
         self.api_url = "http://{}/{}/".format(self.get_cvar("qlx_balanceUrl"), self.get_cvar("qlx_balanceApi"))
 
@@ -105,6 +109,8 @@ def handle_player_disconnect(self, player, reason):
         self.clean_player_data(player)
 
     def handle_new_game(self):
+        self.cache_cvars()
+
         # reset ratings cache on start
         if self.game.state == "warmup":
             with self.ratings_lock: