How to replace Rspec's ENV[“RAILS_ENV”] ||= 'test' deprecated in Rails 3.0?

Question

I'm using rails (3.0.4) and rspec-rails (2.5.0). When I runrails generate rspec:install it producesspec_helper.rb` that contains this line:

ENV["RAILS_ENV"] ||= 'test'

When I run rake spec I get this warning on in the terminal:

DEPRECATION WARNING: RAILS_ENV is deprecated. Please use ::Rails.env.

This isn't as annoying since that only runs once inside my Spork.prefork, but I'd like to get past that deprecation if possible. I'm new to Rails and haven't found mention of this in the rspec-rails issues or anywhere else.