[qa#276] fix hammer's gssapi, netconf, postgres actions on Fedora 33 and FreeBSDs

Closes https://gitlab.isc.org/isc-private/qa-dhcp/-/issues/276.

distcheck test run: https://jenkins.aws.isc.org/job/kea-manual/job/distcheck/55/

ut-extended test run: https://jenkins.aws.isc.org/job/kea-manual/job/ut-extended/86/