[feature/auth-refactor] Fix typos causing changes to not work

Replaces short tags with long tags.
Fixes the interface to be an interface and not class in the file.
Removes unnecessary include_once from auth.php.

PHPBB-9734

phpBB/includes/auth/auth.php

@@ -930,7 +930,6 @@ class phpbb_auth
 		global $config, $db, $user, $phpbb_root_path, $phpEx;
 
 		$method = trim(basename($config['auth_method']));
-		include_once($phpbb_root_path . 'includes/auth/auth_' . $method . '.' . $phpEx);
 
 		$class = 'phpbb_auth_provider_' . $method;
 		if (class_exists($class))

phpBB/includes/auth/provider_apache.php

@@ -1,4 +1,4 @@
-<?
+<?php
 /**
 *
 * @package auth

phpBB/includes/auth/provider_db.php

@@ -1,4 +1,4 @@
-<?
+<?php
 /**
 *
 * @package auth

phpBB/includes/auth/provider_interface.php

@@ -1,4 +1,4 @@
-<?
+<?php
 /**
 *
 * @package auth
@@ -20,7 +20,7 @@ if (!defined('IN_PHPBB'))
  *
  * @package auth
  */
-class phpbb_auth_provider_interface
+interface phpbb_auth_provider_interface
 {
 	/**
 	 * Checks whether the user is currently identified to the authentication

phpBB/includes/auth/provider_ldap.php

@@ -1,4 +1,4 @@
-<?
+<?php
 /**
 *
 * @package auth