dns: don't publish env vars to non-dns scripts

dns: don't publish env vars to non-dns scripts

With --dns-updown in place we no longer need --dns option related vars in
the environment for other script hooks. Code for doing that is removed and
the function to set --dns stuff made static, for internal use only.

Change-Id: I3fb01ab76cf3df0874ba92e08f371d17607a8369
Signed-off-by: Heiko Hund <heiko@ist.eigentlich.net>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20250517092637.2103-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/search?l=mid&q=20250517092637.2103-1-gert@greenie.muc.de
Signed-off-by: Gert Doering <gert@greenie.muc.de>