remove deprecated rspec-system-serverspec includes

See https://github.com/puppetlabs/rspec-system-serverspec/pull/11

Gemfile

@@ -9,6 +9,5 @@ group :rake do
   gem 'puppet-blacksmith'
   gem 'librarian-puppet-maestrodev'
   gem 'rspec-system-puppet',     :require => false
-  gem 'serverspec',   '~> 0.11.0', :require => false
   gem 'rspec-system-serverspec', :require => false
 end

spec/spec_helper_system.rb

@@ -1,8 +1,6 @@
 require 'rspec-system/spec_helper'
 require 'rspec-system-puppet/helpers'
 require 'rspec-system-serverspec/helpers'
-include Serverspec::Helper::RSpecSystem
-include Serverspec::Helper::DetectOS
 include RSpecSystemPuppet::Helpers
 
 RSpec.configure do |c|