Praise be to Allah the Lord of the Worlds.
Scholars stated that in case of revocable divorce a woman is considered a wife, because the marriage contract isn`t terminated. Therefore, if the husband dies, then she inherits him and observes Iddah following death of husband, and the days of Iddah which she observed following revocable divorce don`t count.
Ibn Hajar says, "If the husband dies after revocable divorce, the wife observes the Iddah following death of husband while the days of Iddah which she observed following revocable divorce don`t count, and her maintenance expires."{Moghni Al-Mohtajj, 8/251}. And Allah the Almighty knows best.