config/Param: remove unused "used" flag

src/config/Global.cxx

@@ -77,10 +77,7 @@ void config_global_check(void)
 const ConfigParam *
 config_get_param(ConfigOption option) noexcept
 {
-	auto *param = config_data.params[unsigned(option)];
-	if (param != nullptr)
-		param->used = true;
-	return param;
+	return config_data.params[unsigned(option)];
 }
 
 const ConfigBlock *

src/config/Param.hxx

@@ -38,12 +38,6 @@ struct ConfigParam {
 
 	int line;
 
-	/**
-	 * This flag is false when nobody has queried the value of
-	 * this option yet.
-	 */
-	bool used = false;
-
 	explicit ConfigParam(int _line=-1)
 		:line(_line) {}