monkey_patch.rb

require 'chef/resource/deploy'
require 'chef/provider/deploy/revision'

class Chef
  class Resource
    class Deploy

      def before_rollback(arg=nil, &block)
        arg ||= block
        set_or_return(:before_rollback, arg, :kind_of => [Proc, String])
      end

    end
  end
end

class Chef
  class Provider
    class Deploy
      class Revision

        def action_rollback
          callback(:before_rollback, @new_resource.before_rollback)
          super
        end

      end
    end
  end
end