By TOM SHANAHAN Three takes from Duke (2-5, 1-5 ACC) winning 53-19 over Charlotte (2-2, 2-1 Conference-USA) Saturday night at Wallace Wade Stadium. STATE STATURE PRESERVED Duke’s credibility was at stake as an ACC member and Power 5 football program facing an upstart. The Blue Devils had suffered enough frustrating losses with turnovers and inconsistent play wasting opportunities to beat Boston College, Virginia, Virginia Tech and N.C. State. They couldn’t afford a loss to an instate, Group of…