Add protocol imap, imaps, ftp and smtp for credential-osxkeychain.
Signed-off-by: NXidorn Quan <quanxunzhen@gmail.com>
Acked-by: NJohn Szakmeister <john@szakmeister.net>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>