Prior to 0.2.0, None was returned if you requested a non-existent project, e.g.
distlib.locators.locate('sdflksjdfsadfsadfad', prerelease=True). Now it's returning the empty dict. Since
locate() is supposed to return an instance of
Distribution on success I assume this is a bug and
None should actually be returned.
Discovered thanks to https://travis-ci.org/brettcannon/caniusepython3/builds/44681756