Fix Ubuntu integration tests.

Ubuntu changed the name of the software-properties package, breaking tests. Details here: https://bugs.launchpad.net/ubuntu/+source/ubuntu-meta/+bug/439566
Merge branch 'unit-tests' of https://github.com/cachedout/salt into unit-tests

* 'unit-tests' of https://github.com/cachedout/salt:
  Auth system unit testing framework.
  Optimize imports.
  Minor spelling change.