s3:lib/util_sock: listen on IPv6 addresses with IPV6_ONLY (bug #7383)

s3:lib/util_sock: listen on IPv6 addresses with IPV6_ONLY (bug #7383)

This avoids getting IPv4 addresses as mapped IPv6 addresses
(e.g. ::ffff:192.168.0.1).

Before the bahavior was inconsistent between operating system
and distributions. Some system have IPV6_ONLY as default.

Now we consistently get AF_INET for IPv4 addresses and AF_INET6
for IPv6 addresses.

It also makes it possible to listen only on IPv6 now
as "::" doesn't imply "0.0.0.0" anymore. Which also
avoids confusing log messages that we were not able to
bind to "0.0.0.0".

metze
(cherry picked from commit a3a38ee90ab4ab2be68ac71d9c581daa6b9ee189)
(cherry picked from commit c4c49be416aeac890628c9a9f2fd7975860884d4)