Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 12599)
+++ wp-includes/functions.php	(working copy)
@@ -3397,7 +3397,6 @@
 		return false;
 	}
 
-	@date_default_timezone_set( $timezone_string );
 	$timezone_object = timezone_open( $timezone_string );
 	$datetime_object = date_create();
 	if ( false === $timezone_object || false === $datetime_object ) {