John Kerry's former crew mates vouch for his Vietnam war heroics in a documentary being released in the midst of a campaign debate about his actions as a swift boat skipper. "Brothers in Arms," a first film by journalist Paul Alexander, features Kerry and four men who served with him on Patrol Craft 94, the last of three boats he commanded during the war and the one from which he won the Silver Star for chasing down and killing a combatant who threatened his crew with a rocket. . . . In "Brothers in Arms," opening at a New York...