compat_resource deprecated

[bablakely]

When trying to install/upload os-hardening (or compat_resource directly) with knife, it now fails with an error about basename in /opt/chefdk/embedded/lib/ruby/gems/2.4.0/gems/chef-13.6.4/lib/chef/knife/cookbook_site_download.rb:108. Upon further inspection, this appears to be a reference to the name of the replacement repository provided by the supermarket. In the case of compat_resource, there is none, so a "no implicit conversion of nil into String (TypeError)" is thrown at this line during the install of compat_resource and the whole process fails. Thus os-hardening can no longer install cleanly (at least using knife). Fix is simply to remove the compat_resource dependency from metadata.rb, but this will break functionality for older clients.