Description:
------------
This bug concerns 5.1beta1 / Apache 1.3 / MySQL 4.0.12 
When using the MySQL-Driver for a new PDO-Object, the webserver (Apache 1.3) stalls. The MySQL-Log:
4 Query       SET AUTOCOMMIT=1
and then in an infinite loop:
		      4 Query       ROLLBACK
		      4 Query       ROLLBACK
		      ...
the MySQL-log filled quickly with that last line (about 12MB in 30 seconds). Server had to be killed.
Additionally, phpinfo() tells: "PDO Driver for MySQL 3.x Client Libraries", instead of expected 4.x



Reproduce code:
---------------
$dsn = "mysql:host=localhost;dbname=xxxx";
$user = "xxxx";
$pass = "xxxx";

try {
	$p =& new PDO($dsn,$user,$pass);
}  catch(PDOException $e) {
	echo $e->getMessage() . "\n";
} 

Expected result:
----------------
PDO-Connection to MySQL

Actual result:
--------------
See above.