(Adds detail) By Martyn Herman RIO DE JANEIRO, Aug 14 (Reuters) - Jason Kenny showed fellow Briton Callum Skinner a clean set of wheels to defend his track cycling sprint title on Sunday, powering to his fifth Olympic gold medal. Kenny, who was a team mate of Skinner's when Britain won the team sprint earlier in the week, has now won as many gold medals as fellow cyclist Bradley Wiggins. Wiggins took his fifth gold and eighth Olympic medal by winning the team pursuit on Friday, and Kenny could match him when he contests the keirin here. More...