Description:
------------
mysql bit column when there are values b'0' and b'1' fetched by PDO as empty strings ""

Test script:
---------------
<?php
/**
DROP TABLE IF EXISTS `bit_values` CASCADE;

CREATE TABLE `bit_values` (
  `id`      INT(11) NOT NULL AUTO_INCREMENT,
  `val` bit(1) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `bit_values` (id, val) VALUES (1, b'0'), (2, b'1');
 */
$pdo = new PDO(
    'mysql:host=localhost;dbname=dbname',
    '',
    ''
);
$sth = $pdo->prepare("SELECT * FROM bit_values");
$sth->execute();
$r = $sth->fetchAll(PDO::FETCH_ASSOC);
echo '<pre>'; var_dump($r); echo '</pre>'; die();



Expected result:
----------------
 array(2) {
  [0]=>
  array(2) {
    ["id"]=>
    string(1) "1"
    ["val"]=>
    string(1) "0"
  }
  [1]=>
  array(2) {
    ["id"]=>
    string(1) "2"
    ["val"]=>
    string(1) "1"
  }
}

Actual result:
--------------
 array(2) {
  [0]=>
  array(2) {
    ["id"]=>
    string(1) "1"
    ["val"]=>
    string(1) ""
  }
  [1]=>
  array(2) {
    ["id"]=>
    string(1) "2"
    ["val"]=>
    string(1) ""
  }
}