Move mocking of is_valid_server_info to fixture

test_managercli was mock.patch'ing is_valid_server_info
at module scope for use for it's tests, but other test
modules call mock.patch.stopall() which would stop it
as well. So is_valid_server_info would sometimes be not
mocked, depending on test order. Some tests always fail
if it's not mocked. So move it into SubManFixture.setUp
Make logutil tests assert something.

mock.patch.dict os.environ for the the debug tests, so
the os.environ doesn't pollute other tests.