versioncmp specifies that arguments are strings

[benjunmun]

This change becomes required when using the future parser in puppet 3. I expect it would also be necessary when using puppet 4.

[bowlofeggs]

It seems that Travis is unhappy with this change. Also, we require commits to be atomic, so please squash your commits.

[benjunmun]

I've squashed the commits; sorry about that.

Some of the builds are still failing, but as far as I can tell, they're failing in the same way that the current head is failing - I believe the failed cases are unrelated to my change. It may be this issue? rspec/rspec-core#1864

[bowlofeggs]

Thank you for the contribution, but the Pulp team has decided to discontinue support for this repository:

#27

Please consider using and contributing to the Katello project's puppet-pulp repository as an alternative, and I apologize for any frustration that this decision may cause you.