logging: error string always in parentheses

src/knot/conf/conf.c

src/knot/ctl/process.c

src/knot/ctl/remote.c

src/knot/dnssec/zone-events.c

src/knot/dnssec/zone-keys.c

src/knot/main.c

src/knot/modules/dnstap.c

src/knot/modules/synth_record.c

src/knot/nameserver/ixfr.c

src/knot/nameserver/process_answer.c

src/knot/nameserver/update.c

src/knot/server/journal.c

src/knot/server/net.c

src/knot/server/server.c

src/knot/zone/contents.c

src/knot/zone/events.c

src/knot/zone/zone-load.c

src/knot/zone/zone.c

src/knot/zone/zonefile.c