Previously, named would run with a configuration where *-source-v6 (notify-source-v6,
transfer-source-v6 and query-source-v6) address and port could be simultaneously used
for listening. This is no longer true for BIND 9.16+ and the code that would do
interface adjustments would unexpectedly disable listening on TCP for such interfaces.
Resolves: rhbz#1999691
