Fix for chef 12.6+

[KhaimovMR]

Description

[Describe what this change achieves]

Issues Resolved

[List any existing issues this PR resolves]

Check List

• All tests pass. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/TESTING.MD
• New functionality includes testing.
• New functionality has been documented in the README if applicable
• All commits have been signed for the Developer Certificate of Origin. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/CONTRIBUTING.MD

[tas50]

So the use of the class_eval actually breaks Chef 13, which I'm working on getting full compatibility for. This cookbook is going to have to stay 12.7+ as a requirement in order to work on 12.7 - 13.X. See #59 for more details