Get dujour working with Puppet Server 2.0.0 RC

This is a nice to have for puppetserver 2.0.0 RC but not a blocker. It is a blocker for GA.

We need to bring Preben's improvements to the version check library at https://github.com/puppetlabs/puppet-server/pull/448 into the 2.0.0 branch as quickly as possible so that we can get good information about the RC versions.

Aaron has said this is not a blocker for RC, but it should be fixed as soon as possible along the path to GA.
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Risk assessment: High (QA to perform Functional Review and to make an automated test)
Probability: High (This feature has broken in the past)
Severity: High (When this breaks, we don't get information back from the customers about what version of puppetserver is running.)