Description:
------------
SQL Query like INSERT, inside a function called by register_shutdown_function() doesn't work on PHP 5.0.5 but work perferctly in PHP 5.0.4 and before or with MySQL extension.

Note: the MySQL link identifier is created and passed in arguments of shutdown function.

Reproduce code:
---------------
function cb_shutdown( $lk ) {
 mysqli_query($lk, "INSERT INTO `log`
 (`ip`, `data`)
 VALUES ('127.0.0.1', 'test')");
}

$link = mysqli_connect( "localhost", $db_user, $db_pass, $db_name);
register_shutdown_function("cb_shutdown", $link);


Expected result:
----------------
A new record in `log` table.

Actual result:
--------------
No record added and warning:
Couldn't fetch mysqli