Check_MK Werk 2207: Fix exception in rule based notifiations with Nagios core and event type filter

ID: 2207 Title: Fix exception in rule based notifiations with Nagios core and event type filter Component: Notifications Level: 2 Class: Bug Fix Version: 1.2.7i1 When using Nagios as a core and the list of allowed events contains flapping or downtime events and the previous hard state cannot correctly be determined (due to <tt>max_check_attempts</tt> being greater as) then an exception could have happened. This has been fixed.