Description:
------------
When running multiple queries with one exec, the queries
succeed (or appear to succeed, with no exception), but a
subsequent query fails with 2013 Lost connection to MySQL server during query

I'm using MySQL 5.0.20a-Debian_2-log on Debian Linux. Client library version is 

"PDO Driver for MySQL, client library version => 5.0.22"

This is similar to "bogus" bug #37732 which affects mysqli - But in PDO there is no way to manually "consume" the empty result sets from an exec() - PDO should really do it automatically.

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

error_reporting(E_ALL);
	 
function DbInit()
{
	global $db;
	
	$options = array();
	
	$connstr = "mysql:host=localhost;dbname=test";
	$db = new PDO($connstr, "root", "", $options);
	$db->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
	
	// Make sure our connections use utf8.
	$db->exec("SET NAMES utf8");
}

function TestBatch()
{
	global $db;
	$sql = "CREATE TEMPORARY table b (t varchar(20))";
	$sql2 = " INSERT INTO b VALUES ('hello')";
	/* This works
	$db->exec($sql);
	$db->exec($sql2);
	*/
	/* This fails because the subsequent query gives 2013 Lost connection to MySQL server during query */
	$db->exec($sql . ";" . $sql2);	
	$sth = $db->query("SELECT * FROM b");
	var_dump($sth->fetchAll(PDO::FETCH_ASSOC));
}

DbInit();
TestBatch();

?>

Expected result:
----------------
array(1) {
  [0]=>
  array(1) {
    ["t"]=>
    string(5) "hello"
  }
}


Actual result:
--------------
Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000]: General error: 2013 Lost connection to MySQL server during query' in /home/mark/progs/phptest/pdobatch.php:30
Stack trace:
#0 /home/mark/progs/phptest/pdobatch.php(30): PDO->query('SELECT * FROM b')
#1 /home/mark/progs/phptest/pdobatch.php(35): TestBatch()
#2 {main}
  thrown in /home/mark/progs/phptest/pdobatch.php on line 30