WACO — Richie was the first to die, then Diesel, then Dog. Whatever else they were in life, the men with the biker nicknames were Cossacks, loud and proud and riders in a Texas motorcycle gang. And that’s what got them killed, shot to death in a brawl with a rival gang in the parking lot of a Texas “breastaurant” that advertised hot waitresses and cold beer. “I saw the first three of our guys fall, and we started running,” said their brother-in-arms, another Cossack, who said he was there a week ago when the shooting started at the Twin...