Fix Ubuntu 14.04 tests for now.

This doesn't fix the root cause of the issue, such as the fact that
dpkg can't do wildcard removals, and the uninstall fails when you're
passing in a version number like this, but THIS test doesn't care, it
just wants to make sure the deprecation warning appears in the first
place.

This does however make the tests pass on 14.04.
Merge pull request #427 from apenney/fix-1404-tests

Fix Ubuntu 14.04 tests for now.