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 8ac1d4e0)

Closes #2852 (closed)