Do not vendor cookbooks using Berkshelf anymore

Instead, use the Berkshelf support in knife-solo and the
vagrant-berkshelf plugin on Vagrant

cookbooks/logrotate/libraries/matchers.rb

@@ -1,11 +0,0 @@
-if defined?(ChefSpec)
-  ChefSpec.define_matcher :logrotate_app
-
-  def enable_logrotate_app(resource)
-    ChefSpec::Matchers::ResourceMatcher.new(:logrotate_app, :enable, resource)
-  end
-
-  def disable_logrotate_app(resource)
-    ChefSpec::Matchers::ResourceMatcher.new(:logrotate_app, :disable, resource)
-  end
-end