Print, but don't fail on deprecation notice

A simple change so that deprecation notices are printed, but don't cause test failures. A possible fix for issue #27.
I don't think the description here is accurate, as the `elsif` only checks for an exact match against version 3.6. You might wrongly interpret from that version 3.7 will only produce one deprecation warning from the context description.

I'm not sure if this test (for Puppet 3.6) adds much value - I think the test above is sufficient.