Update rspec dependency

because rspec-its requires rspec-core >= 2.99.0.beta1
Remove fedora/service_spec.rb

It depends on specinfra and I will remove tests depending on specinfra
in the future.

Now fedora/service_spec.rb fails, so I remove it because I will remove
it after all.
Merge pull request #440 from serverspec/update-rspec-core-dependency

Update rspec core dependency