Implements hook_user_login().
Save openid_identifier to visitor cookie.
function openid_user_login($edit, $account) {
if (isset($_SESSION['openid'])) {
// The user has logged in via OpenID.
user_cookie_save(array_intersect_key($_SESSION['openid']['user_login_values'], array_flip(array(
'openid_identifier',
))));
unset($_SESSION['openid']);
}
}