tests: require repo in test-check-debian.t When installed with pip/setup.py, the installation lacks debian/ directory, so the test was always failing. We could check the existence of the directory manually, but I think it makes more sense (and is easier) to just require running this test while having the whole repo. This way we (who can do something about it) can see if there are debian-related problems, and users (who can't) don't, regardless of the way they obtained evolve.