remove default timezone #411

Lib/Constants.php

@@ -12,10 +12,6 @@
  * @license   http://www.opensource.org/licenses/mit-license.php MIT License
  */
 
-// Date.timezone
-if (!ini_get('date.timezone')) {
-    date_default_timezone_set('Asia/Shanghai');
-}
 // Display errors.
 ini_set('display_errors', 'on');
 // Reporting all.