The last movie Clooney directed, “Good Night, and Good Luck,” was an urgent tribute to journalistic integrity. Oddly, there isn’t a shred of urgency about “Leatherheads.” Nothing much is at stake: the romantic triangle is no contest from the get-go and Lexie’s ambition, heavily built up in Duncan Brantley and Rick Reilly’s script, is pretty much forgotten about. “Leatherheads” also wants us to mourn the passing of the anarchic, rough-and-tumble pro-football scene before it became a rule-bound, efficient business, but Clooney exhibits so little interest in football that he forgets to show us what was so good about the good old gridiron days. The great ’30s comedies had edge, bite and relentless forward momentum. “Leatherheads” is laid-back, amiable and terminally tepid.