DOTHAN, Ala. — On a humid summer day in 1972, Hillary Rodham walked into this town’s new private academy, a couple of cinder-block classrooms erected hurriedly amid fields of farmland, and pretended to be someone else. Playing down her flat Chicago accent, she told the school’s guidance counselor that her husband had just taken a job in Dothan, that they were a churchgoing family and that they were looking for a school for their son