Problem
=========================
Since Mysql server 8.0.14, we cannot setup a replication group using
mysql-shell (and probably by using mysql client).

The server fails with these messages (note the "cannot use port xxx"
and the "adding ipv6 localhost to whitelist" even though no ipv6 is
available)

Analysis and Fix
=========================
When adding ipv6.disable=1 to a into a boot configuration, we are left
without kernel support for IPv6. As such, we can't have calls that
use directly AF_INET6 or "::1". Remove all hardcoded AF_INET6
assumptions.

ReviewBoard: 21337