Enable Ruby 2.0.0/Rails 3.2 build
Workaround for failing build on Ruby 1.8.7

* https://github.com/bundler/bundler/issues/2784
* https://github.com/rspec/rspec-expectations/commit/d2e3d97e5f0f1e23061f26376d2a752292c2a5d2
Merge branch 'p-rcook-ruby-1.8.7'
Merge branch 'p-rcook-rails-3.2'