Checkmk Werk 15479: Fix error message in alert.log complaining about missing contacts

ID: 15479 Title: Fix error message in alert.log complaining about missing contacts Component: alerts Level: 1 Class: Bug fix Version: 2.1.0p27 On alert handler execution, an error message like "Error on completing raw context: Missing 'CONTACTS' in raw notification context. It should always be available when using the Microcore." was shown in ~/var/log/alert.log. The alerts were processed correctly, this error message was just misleading.