HARARE (Reuters) - Zimbabwe s former vice president Emmerson Mnangagwa will be sworn in as president on Friday following the resignation of Robert Mugabe, the parliament speaker said on Wednesday. Speaker Jacob Mudenda said the ruling party ZANU-PF had informed him it has nominated Mnangagwa to fill the vacancy of the office of president, replacing the 93-year-old Mugabe who had clung on for a week after an army takeover. 