Update tests for rspec-puppet 2

This patch uses `catalogue` instead of `subject` for the raise_error
matcher since `subject` is not evaluated the way it used to be. We also
unpin rspec-puppet.

Gemfile

@@ -3,7 +3,6 @@ source ENV['GEM_SOURCE'] || "https://rubygems.org"
 group :development, :unit_tests do
   gem 'rake',                    :require => false
   gem 'rspec-core', '3.1.7',     :require => false
-  gem 'rspec-puppet', '~> 1.0',  :require => false
   gem 'puppetlabs_spec_helper',  :require => false
   gem 'puppet-lint',             :require => false
   gem 'simplecov',               :require => false

spec/classes/ntp_spec.rb

@@ -363,8 +363,8 @@
         })
         end
 
-        it { expect{ subject }.to raise_error(
-          /^The ntp module is not supported on an unsupported based system./
+        it { expect{ catalogue }.to raise_error(
+          /The ntp module is not supported on an unsupported based system./
         )}
       end
     end