Also authirize the administrator of the website to make translation

The administrator of the drupal website (userid = 1) should also be authorize to make translation even if he is not part of the og

if (!empty($user->og_groups[$locale])) {
$permission = !empty($user->og_groups[$locale]["is_admin"]) ? 2 : $user->og_groups[$locale]["is_active"];
}

would become something like :

if (!empty($user->og_groups[$locale]) || ($user->uid == 1)) {
$permission = ((!empty($user->og_groups[$locale]["is_admin"])) || ($user->uid == 1 ))? 2 : $user->og_groups[$locale]["is_active"];
}