A better way to support RFC5424/IETF syslog format.

12-STABLE, 13-STABLE, and 14-CURRENT now support RFC5424 by default.

PR: 252613
Reported by: leres
Reviewed by: Peter Czanik <peter.czanik@oneidentity.com>

		Balabit (a OneIdentity company) / syslog-ng upstream