As the curtain opens on the second act of Don Pasquale, I hear a rustle of discomfort. Donizetti’s opera has not been seen at La Scala since 1994. Its restoration, on the orders of a new music director, sets off a critical flutter and Davide Livermore’s new production, set in the Cinecittà film studio during the 1950s dolce vita, seems designed to tweak the Roman nose of national vanity.