For ex-champs Kamaru Usman and Dricus du Plessis, UFC Oklahoma City looks like a no-man's land

They should’ve called this weekend’s fight card in Oklahoma City, “UFC Fight Night: No Man’s Land,” because that’s kind of what it feels like. Not only is it happening in the middle of the country just a week after the Conor McGregor vortex known as UFC 329, it features a pair of fighters with abstract bearings in the UFC ranks — the South African former middleweight champion Dricus du Plessis, and the former welterweight champion Kamaru Usman. So this is where they shuttle off those fighters who don’t fit neatly into any title picture. To “The Big Friendly,” the proud…