Description:
------------
PDO does not cast a variable with boolean type in bindValue, does not do execute and is silent.

I should cast manually - (int).

Reproduce code:
---------------
CREATE TABLE `test` (
  `test` tinyint(1) NOT NULL default '0'
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

$Db = new PDO('mysql:host=localhost;dbname=test', 'root', '');
$Db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$Db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);

$boolean = 1;
$Pdo = $Db->prepare('INSERT INTO test VALUES (:boolean)');
$Pdo->bindValue(':boolean', isset($boolean), PDO::PARAM_INT);
$Pdo->execute();

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

Actual result:
--------------
array(0) { }