Simplify arena map typemapper

src/de/steamwar/bungeecore/commands/TypeMappers.java

@@ -79,8 +79,7 @@ public class TypeMappers {
             public String map(CommandSender commandSender, String[] previousArguments, String s) {
                 if (previousArguments.length == 0) return null;
                 if (s.equalsIgnoreCase("random")) return "random";
-                ArenaMode arenaMode = ArenaMode.getByChat(previousArguments[previousArguments.length - 1]);
-                return arenaMode.convertToRealMapName(s);
+                return ArenaMode.getByChat(previousArguments[previousArguments.length - 1]).convertToRealMapName(s);
             }
 
             @Override