update travis test matrix

* change puppet 3.2.0 -> 3.2.1 as 3.2.0 was a broken release see
  http://docs.puppetlabs.com/puppet/3/reference/release_notes.html#puppet-321
* un-exclude ruby 1.8.7 / puppet 3.2.1; fully supported and I have this
  in production
* add puppet 3.3.0