If we built git without curl, we can't actually test against
an http server. In fact, all of the test scripts which
include lib-httpd.sh already perform this check, with one
exception: t5540. For those scripts, this is a noop, and for
t5540, this is a bugfix (it used to fail when built with
NO_CURL, though it could go unnoticed if you had a stale
git-remote-https in your build directory).
Noticed-by: NJunio C Hamano <junio@pobox.com>
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>