Logging to journald misses error messages

[julianbrost]

That's the way we currently typically log errors:

icingadb/pkg/icingadb/ha.go

Lines 392 to 397 in 77ccab2

	log := h.logger.Debugw
	if attempt > 3 {
	log = h.logger.Infow
	}
	log("Can't update or insert instance. Retrying", zap.Error(err))

When running journalctl -u icingadb, that means you only see something like that:

icingadb[12345]: high-availability: Can't update or insert instance. Retrying

Yes, technically the full error message is logged as well (as extra fields attached to the message) and we did #743, but let's face it: if the most obvious way to view the logs hides the actual error messages, that's a bug.