Checkmk Werk 15120: Fix possible error on using host or service level filter

ID: 15120 Title: Fix possible error on using host or service level filter Component: Multisite Level: 1 Class: Bug fix Version: 2.2.0i1 If you used host or service level filter in views with an event datasource, e.g. "Events of host & services", the error "Internal error: 'NoneType' object is not subscriptable" occurred.