We do not currently test authentication for smart-http repos
at all. Part of the infrastructure to do this is recognizing
that auth/smart is indeed a smart-http repo.

The current apache config recognizes only "^/smart/*" as
smart-http. Let's instead treat anything with /smart/ in the
URL as smart-http. This is obviously a stupid thing to do
for a real production site, but for our test suite we know
that our repositories will not have this magic string in the
name.

Note that we will route /foo/smart/bar.git directly to
git-http-backend/bar.git; in other words, everything before
the "/smart/" is irrelevant to finding the repo on disk (but
may impact apache config, for example by triggering auth
checks).
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>