Merge lp://qastaging/~brian-murray/ubuntu-release-upgrader/test-ordering into lp://qastaging/ubuntu-release-upgrader

The test test_sources_list.py would fail if run by itself (with a NoDistroTemplate Exception) and would only succeed if it was run after test_dist_ugprade_fetcher_core.py. This is because test_dist_upgrade_fetcher_core.py downloads an ubuntu-release-upgrader tarball which includes Ubuntu.info and Ubuntu.mirrors from python-apt. Additionally, something in the dist upgrade fetcher test would also set the working directory to '/tmp/ubuntu-release-upgrader-XYZ' which contained the Ubuntu.* files.

Then test_sources_list.py uses DistUpgradeController which sets the following:

self.sources = SourcesList(matcherPath=".")

So when the test is run without test_dist_upgrade_fetcher_core.py we check the current directory for python apt templates and find none, so the test fails. I've resolved this by making the matcherPath dynamic and including Ubuntu.info and Ubuntu.mirrors in the tests' data directory.