Point to 7.0.0.alpha.0 of Ohai.
Fix chef spec infra to use OHAI correctly.
Bump the chef version number for an alpha build that works with OHAI 7.
Fix the Ohai resource for Ohai 7.
Remove the unneeded running of "os" plugin.
Modify the Gemfile so that specs can run in CI.
Merge pull request #1214 from opscode/ohai-resource-fix

Ohai 7 Compatibility for Chef