Prevent inconstitent /data/trafic_limiter.php due to file read while writing

(cherry picked from commit 71a7f6adaea9a86a84fa8ebbcb9e5c506a785527)

Conflicts:
	index.php

lib/persistence.php

@@ -105,7 +105,7 @@ abstract class persistence
     {
         self::_initialize();
         $file = self::$_path . '/' . $filename;
-        file_put_contents($file, $data);
+        file_put_contents($file, $data, LOCK_EX);
         chmod($file, 0705);
         return $file;
     }