By TOM SHANAHAN The old coach knew what he was talking about on Saturday morning. Lee Corso, the 85-year-old ESPN College Gameday host, thought it odd N.C State, with a 3-1 record, was only a 4.5-point favorite at home over a Duke, a team with a 1-4 mark. “Somebody knows something,” said Corso as he predicted a Duke upset. Despite N.C. State (4-1) winning 31-20 over Duke (1-5) on Saturday at Carter-Finley Stadium, the Blue Devils could have…