git: Wrong parsing of ssh urls with IPv6 literals ignores port

If we encounter an address part shaped like "[HOST]:PORT", we skip the opening bracket and replace the closing one with a NUL. The variable host then points to HOST and we've cut off the PORT part. Thus, when we go looking for it using host a bit later, we can't find it. Start at end instead, which either points to the colon, if present, or is equal to host. Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>