Fix ubuntu issues that broke tests.

Puppetlabs apt introduced a change that required a debian
specific fact that wasn't being set in the spec tests. This
patch adds it.

Change-Id: Ia8fb3a5d0b01bf58eea583f2f129b48b4ce9564d
(cherry picked from commit 0cbddbcea0f3c9932863695d731f079fdd2b1be2)