Checkmk Werk 15256: Fixed handling of unknown time periods when using the Nagios core

ID: 15256 Title: Fixed handling of unknown time periods when using the Nagios core Component: Livestatus Level: 1 Class: Bug fix Version: 2.3.0b1 An unknown/unspecified time period has to be interpreted as "24X7", but there was a regression from 1.6.0 to 2.0.0 which could lead to segfaults when using Livestatus (pointed out by Gerald Eisenkölbl via feedback). This has been fixed.