for-each-ref: Allow a trailing slash in the patterns

More often than not, I end up using something like refs/remotes/ as the pattern for for-each-ref, but that doesn't work, because it expects to see the slash in the ref name right after the matched pattern. So teach it to accept the slash as the final character in the pattern as well. Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>