Description:
------------
Hello,

when catching a connection error in a class extending PDO, the object is not destroyed before end of script.
It's really not a big bug, but as the instance is not usable (no instance is returned at all) it should be destroyed no ?



Reproduce code:
---------------
<?php

class PDOtest extends PDO
{
	public function __construct( $dsn, $user, $password )
	{
		try
        {
        	parent::__construct( $dsn, $user, $password );
        } catch( PDOException $e ) {
            echo 'there is an error... but continue the script', PHP_EOL;
        	return;
        }
	}

    public function __destruct()
    {
        echo 'DESTRUCT', PHP_EOL;
    }
}

echo 'CONSTRUCT', PHP_EOL;
$test = new PDOtest( 'mysql:host=localhost;dbname=test', 'baduser', 'orpass' );
var_dump( $test );

echo 'SOME WORKS', PHP_EOL;
?>

Expected result:
----------------
CONSTRUCT
there is an error... but continue the script
DESTRUCT
NULL
SOME WORKS


Actual result:
--------------
CONSTRUCT
there is an error... but continue the script
NULL
SOME WORKS
DESTRUCT