OKLAHOMA CITY (AP) — Former University of Oklahoma running back Mike Gaddis, who former coach Barry Switzer called the best running back from the state of Oklahoma he ever signed, has died. He was 50. Switzer told The Associated Press Tuesday that Gaddis’ father-in-law told him Gaddis died Monday at his home in Oklahoma City. A cause of death was not released. Gaddis signed with OU out of Carl…