Keenum, Yates making it difficult for Kubiak to pick No. 2 quarterback

As they saying goes, teams with two starting quarterbacks have none.  Teams with two backup quarterbacks have a different sort of problem. For the Texans, it’s a good problem to have. Operating as the second quarterback on Saturday night, Case Keenum continued his stellar second preseason, completing 11 of 18 passes for 150 yards and…