Como posso desativar o log de mensagens de pipeline de ativos (sprockets) no Ruby on Rails 3.1?

As engrenagens tendem a ser bastante detalhadas no log (dev) por padrão em Ruby on Rails 3.1 (RC1): Started GET "/assets/application.css" for 127.0.0.1 at 2011-06-10 17:30:45 -0400 Compiled app/assets/stylesheets/application.css.scss (5ms) (pid 6303) Started GET "/assets/application.js" for...