Check_MK Werk 6437: Fixed event cancelling when no match groups are used

ID: 6437 Title: Fixed event cancelling when no match groups are used Component: Event Console Level: 2 Class: Bug fix Version: 1.6.0i1 Canceling of Event Console events using the message text was not working correctly when using simple string matching instead of regex or mixed types of matches (e.g. regex for the match text and string match for the cancel text) matching. This regression affects all previous 1.5 releases.