By Tony DiZinno It’s a pair of veterans who topped Thursday’s seven-hour practice, with 29-year-old Graham Rahal going into his 11th Indianapolis 500 and 43-year-old Tony Kanaan going into his 17th ‘500 atop the timesheets. — Rahal, 34th on Wednesday, felt it important to “put down a lap” early and eliminate any chatter that he…