efi/http: Enclose literal IPv6 addresses in square brackets

efi/http: Enclose literal IPv6 addresses in square brackets

According to RFC 2732 (https://www.ietf.org/rfc/rfc2732.txt), literal IPv6
addresses must be enclosed in square brackets. But GRUB currently does not
do this and is causing HTTP servers to send Bad Request (400) responses.

For example, the following is the HTTP stream when fetching a config file:

HEAD /EFI/BOOT/grub.cfg HTTP/1.1
Host: 2000:dead:beef:a::1
Accept: */*
User-Agent: UefiHttpBoot/1.0

HTTP/1.1 400 Bad Request
Date: Thu, 05 Mar 2020 14:46:02 GMT
Server: Apache/2.4.41 (Fedora) OpenSSL/1.1.1d
Connection: close
Content-Type: text/html; charset=iso-8859-1

and after enclosing the IPv6 address the HTTP request is successful:

HEAD /EFI/BOOT/grub.cfg HTTP/1.1
Host: [2000:dead:beef:a::1]
Accept: */*
User-Agent: UefiHttpBoot/1.0

HTTP/1.1 200 OK
Date: Thu, 05 Mar 2020 14:48:04 GMT
Server: Apache/2.4.41 (Fedora) OpenSSL/1.1.1d
Last-Modified: Thu, 27 Feb 2020 17:45:58 GMT
ETag: "206-59f924b24b1da"
Accept-Ranges: bytes
Content-Length: 518

Resolves: rhbz#1732765

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
Gbp-Pq: Topic network
Gbp-Pq: Name efi-http-enclose-literal-ipv6-addresses-in-square-br.patch