changeset: DNSSEC and IXFR fixes, more freeing functions.

src/knot/nameserver/ixfr.c

src/knot/nameserver/update.c

src/knot/server/journal.c

src/knot/updates/changesets.c

src/knot/updates/changesets.h

src/knot/zone/events.c

src/knot/zone/zone-load.c

src/knot/zone/zone.c

src/knot/zone/zone.h

tests-extra/tools/dnstest/params.py

tests/changeset.c