Add rspec-puppet tests to aid in verification of new features, fixes, and pull requests

[smerchek]

With three different flavors of supported operation systems, it is past due to add rpec-puppet tests. As this module become more complex, it is important that there is verification of the module via tests. This will also aid in verifying contributions are correct without too much effort.

These tests can later be automated with Travis CI.

[genebean]

@smerchek FWIW, I have rewritten this module completely and have started writing the tests to go with it. If you feel so inclined, you can see it at genebean/genebean-zabbixagent@cc14c93