t5541: simplify and move "no empty path components" test

t5541: simplify and move "no empty path components" test

Commit 9ee6bcd398 (t5541-http-push: add test for URLs with trailing
slash, 2010-04-08) added a test that clones a URL with a trailing slash,
and confirms that we don't send a doubled slash (like "$url//info/refs")
to the server.

But this test makes no sense in t5541, which is about pushing. It should
have been added in t5551. Let's move it there.

But putting it at the end is tricky, since it checks the entire contents
of the Apache access log. We could get around this by clearing the log
before our test. But there's an even simpler solution: just make sure no
doubled slashes appear in the log (fortunately, "http://" does not
appear in the log itself).

As a bonus, this also lets us drop the check for the v0 protocol (which
is otherwise necessary since v2 makes multiple requests, and
check_access_log insists on exactly matching the number of requests,
even though we don't care about that here).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>