PHP5.4 compatibility for empty() function.

admin/check.php

@@ -124,14 +124,14 @@ if (extension_loaded('openssl')) {
 }
 
 // Datetime
-if (!empty(ini_get('date.timezone'))) {
+$timezone = ini_get('date.timezone');
+if (!empty($timezone)) {
     $messages[] = new Message('info', __('Check','date.timezone is set.'));
 } else {
     $messages[] = new Message('warning', __('Check','Consider setting the date.timezone in php.ini.'));
 }
 
 
-
 // The percentage of steps needed to be ready to launch the application
 $errors = 0;
 $warnings = 0;