dns: T5900: fix smoketests for serve-stale-extension and exclude-throttle-address

This fixes commit 199ceb1f0a ("dns: T5900: add dont-throttle-netmasks and
serve-stale-extensions powerdns features") where after the latest review round
the Jinja2 template was inconsitently changed and smoketests were not re-run.

(cherry picked from commit 9baeafa890f7b1d3829df633322fb4288e9ea882)