Checkmk Werk 12979: Fix "Element does not exist anymore" message in notification conditions

ID: 12979 Title: Fix "Element does not exist anymore" message in notification conditions Component: Multisite Level: 1 Class: Bug fix Version: 2.1.0i1 If a notification rule contained conditions for "Match hosts", a message like "Element 'my_host' does not exist anymore" was shown within the conditions column.