Remove the code to adjust listening interfaces for *-source-v6

Remove the code to adjust listening interfaces for *-source-v6

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.

This commit removes the code that would adjust listening interfaces
for addresses/ports configured in *-source-v6 option.

(cherry picked from commit 8ac1d4e0daee6fc785377761da42023127ec2284)