This is the season for old favorites: the holidays, friends, good cheer, the classics. So we went to John’s Grill on Ellis Street just off Powell toward the end of last week to help celebrate the restaurant’s 110th birthday. The place was crowded. A lot of political bigwigs were on hand: the mayor, the police chief, the fire chief, the public defender, a city supervisor or two, Willie Brown shaking hands. State Sen. Scott Wiener brought a framed proclamation.