It doesn’t seem likely that filmmakers will ever grow tired of making boxing films, or that they’ll run out of inspiring athletes to make them about. What’s not to love about a boxing film, anyway? The stories are rife with colorful characters, outsize egos, braggadocious smack talk, personal perseverance, and lots and lots of blood. They write themselves, practically, and “Bleed for This,” the true story of Vinny Paz (Pazienza), slips easily into the already established oeuvre.