By Crispian Balmer ROME (Reuters) – President Sergio Mattarella had already signed a lease on a new apartment and called in the packers, making it clear he wanted to leave the Quirinale Palace the minute his seven-year mandate expired on Feb. 3. But instead, the 80-year-old Mattarella unexpectedly agreed to stay in place on Saturday and prevent a power vacuum, with Italy’s fractious parties unable to pick an alternative figure capable of winning a majority in parliament. “I had other plans, but if needed, I am at your disposition,” parliamentarians quoted the snowy-haired Mattarella as telling…