Removing 2.0.0 CI build.
2.0.0 causes build errors. Travis-CI reports:

Gem::RemoteFetcher::FetchError: Errno::ETIMEDOUT: Connection timed out - connect(2) (https://rubygems.org/gems/rspec-rails-2.14.0.gem)

An error occurred while installing rspec-rails (2.14.0), and Bundler cannot
continue.

Make sure that `gem install rspec-rails -v '2.14.0'` succeeds before bundling.
The command "bundle install --deployment" failed and exited with 5 during install.