BOSTON — A former clerk for the Massachusetts Registry of Motor Vehicles is headed to prison for her role in an identity theft scheme.The U.S. Justice Department says 37-year-old Annette Gracia, of Boston, was sentenced to a year in prison after pleading guilty to one count of illegally producing an identification document.Prosecutors say Gracia was one of four clerks at a Boston RMV location who helped issue identification cards to people who were in the country illegally in exchange for cash.