Code review comment for lp:~vila/bzr/646133-selftest-as-root

Meh, lol, yeah I didn't re-read the code and replied to Martin, I think we all agree the behaviour is the expected one on windows: not_running_as_root is always True. Now whether it's better to be wrong when you're right or right when you're wrong is left as an exercise for the philosopher ;)

Some of the tests I modified *also* check for the supports_posix_readonly feature which see *OR* are already skipped on windows.