Fix a regression introduced by 58dc5a191c0203ea6d98c37df26b0830b3bf8203. The problem is that $user->add_lang() includes language strings from the board root folder instead of the update folder. Because the database updater is run first, the root folder files have not been upgrade yet. Thus, the language strings we're looking for cannot be found. Since the language strings we are looking for have been moved from the install.php language file to acp/attachments.php it should be possible to always find them in either file. When there is an acp/attachments.php file in the update package, it can also be used. We now also loop through all the installed languages as well, because the board could have been installed in a language other than the admin's current language. PHPBB3-9885 PHPBB3-7717