Merge lp://staging/~jcsackett/launchpad/add-security-audit-utility into lp://staging/launchpad

This branch looks fine. There's nothing keeping this from being merged,
but here are a few things to consider:

If comment lines can also start with whitespace, you might want to strip
before looking for the comment character, like so:

    def strip(data):
        data = [d for d in data if not d.strip().startswith('#')]
        return [d for d in data if d.strip() != '']

It would be nice if this were tested to be sure that it reports the
errors you expect it to report (and more importantly, that it doesn't
stop reporting errors in the future when someone breaks it).

Would it be possible to run this at "make" time or as part of the test
suite? It'd be great if buildbot/jenkins would tell us if we introduced
errors that this code can find.

I see that the standard library's ConfigParser wouldn't work for this
use case; you might add a note explaining why you parse the file
yourself.

Since you use the "__metatype__ = type" trick you don't need to subclass
from object when defining SettingsAuditor.

In start_new_section, I don't see why you have to make a copy of
self.observed_settings because you're going to discard it at the end of
the method anyway.

You use "sys.exit(main())" but main doesn't ever return a non-None
value.

Benji--

Thanks for the notes; a fair amount of what you saw were artifacts of the scripts creation--I've cleaned them up, and good spotting on your part.

I think there's a case to hook this up, but like "make lint" I'm not sure it's actually something we always want run--it's not terribly expensive now, and it's only really useful for specific work. We can investigate hooking it in in a future branch; once this lands I'll send out an email to dev about it to start that discussion.

And I have added a quick smoketest that will be run as part of testrunner for it. It's a bit ugly, but the utility stuff is difficult to test.