fix Association Preloader for Rails 3.1
fix Association Preloader for Rails 3.1

rrosenblum/bullet,jay3126/bullet,eileencodes/bullet,rstacruz/bullet,jay3126/bullet,rrosenblum/bullet,dwb/bullet,yakovenkodenis/bullet,yakovenkodenis/bullet,danp60/bullet,theass/bullet,danp60/bullet,hannahbot/bullet,theass/bullet,flyerhzm/bullet,dwb/bullet,rstacruz/bullet,hannahbot/bullet,PikachuEXE/bullet,sideci-sample/sideci-sample-bullet,sho-h/brakefast,flyerhzm/bullet,eileencodes/bullet,flyerhzm/bullet,sideci-sample/sideci-sample-bullet,PikachuEXE/bullet,sho-h/brakefast