[feature/passwords] Use dependency injection for passwords driver helper

The passwords driver helper is now injected into the driver base instead
of being manually loaded.

PHPBB3-11610

phpBB/phpbb/passwords/driver/helper.php

@@ -20,23 +20,12 @@ if (!defined('IN_PHPBB'))
 */
 class phpbb_passwords_driver_helper
 {
-	/** @var phpbb_config */
-	protected $driver;
-
 	/**
 	* base64 alphabet
 	* @var string
 	*/
 	public $itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
 
-	/**
-	* Constructor of passwords driver helper object
-	*/
-	public function __construct($driver)
-	{
-		$this->driver = $driver;
-	}
-
 	/**
 	* Base64 encode hash
 	*