urlmatch: add url_normalize_pattern() helper

urlmatch: add url_normalize_pattern() helper

In a following commit, we will need to normalize a URL glob pattern
(which may contain '*' in the host portion) and extract its component
offsets (host, path, etc.) for separate matching. Let's export a
dedicated helper function url_normalize_pattern() for that purpose.

It works like url_normalize(), but passes allow_globs=true to the
internal url_normalize_1(), so that '*' characters in the host are
accepted rather than rejected.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>