Fix minitests

Fixing a minor typo in .kitchen.yml and removing an apt sources check that is no longer needed due to changes from commit bc33ea5.

There is still a problem with default test:
     2) Error:
   rabbitmq::default#test_0006_accepts AMQP connections:
   LoadError: cannot load such file -- bunny
       /opt/chef/embedded/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
       /opt/chef/embedded/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
       /var/chef/minitest/rabbitmq/default_test.rb:53:in `block (2 levels) in <top (required)>'

I haven't been able to get bunny installed as a chef_gem from within the minitest run yet.