Description:
------------
When using PDO MySQL to select rows for update with PDO::ATTR_EMULATE_PREPARES set to false and PDO::ATTR_ERRMODE set to PDO::ERRMODE_EXCEPTION no exception is thrown when the rows are already locked and a timeout occurs.

Note:
The exception is thrown when PDO::ATTR_EMULATE_PREPARES is not set/set to true or when a parameter is used in the select query.

Instructions on reproducing this: 
Open mysql on cli, and perform queries:
CREATE DATABASE testdb;
USE testdb;
CREATE TABLE test (`id` INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, `value` VARCHAR(30) NOT NULL);
INSERT INTO `test` (`value`) VALUES ('test');

# Before starting the test script open a transaction and lock the table:

BEGIN;
SELECT * FROM `test` FOR UPDATE;

# Now run the script

Test script:
---------------
<?php
$pdo = new PDO('mysql:dbname=testdb;host=localhost', 'username', 'password');
$pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$pdo->beginTransaction();
$statement = $pdo->prepare('SELECT * FROM `test` FOR UPDATE');

$statement->execute();

var_dump(
$statement->fetchAll(), 
$statement->errorCode()
);

$pdo->commit();


Expected result:
----------------
Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction in test-pdo.php:14
Stack trace:
#0 test-pdo.php(14): PDOStatement->execute()
#1 {main} thrown in test-pdo.php on line 14

Actual result:
--------------
array(0) {
}
string(5) "00000"