(#6818) Stop from getting Rails 3 named_scope deprecation warning
We want our Rails models in Puppet to work under Rails 2 or 3, but we
don't want the deprecation warnings since we can't control what version
of Rails the client is running.
DEPRECATION WARNING: Base.named_scope has been deprecated, please use
Base.scope instead
Reviewed-by: Nick Lewis <nick@puppetlabs.com>