fixed stats being logged despite loglevel being <= WARNING

(cherry picked from commit 4a988b7a)

lib/SimpleSAML/Logger.php

@@ -257,7 +257,7 @@ class Logger
      */
     public static function stats($string)
     {
-        self::log(self::NOTICE, $string, true);
+        self::log(self::NOTICE, $string, self::$logLevel >= self::NOTICE);
     }