1. We should assert flavor.set_keys() is called correctly
or not called in ``set flavor`` unit tests.
2. Commit c7e6973ff50ff84af9ad55f7bdaeeea83ae40f0b from me
removed test_flavor_unset_no_project which used to test
if --project was specified as '', and assert CommandError
was raised, which is incorrect. So I removed it. But after
looking into the code, I think we should not remove it,
but specify nothing after --project, and assert
ParserException was raised. So in this patch, we fix it
as so.
('--project', '') --> ('--project')
assert CommandError --> assert ParserException
Change-Id: Ifd33c72d5b7581aaabffb09e9b5e38ecc67e18c0
c4b590748a