Checkmk Werk 11491: Nagios: Fix broken config reason displaying

ID: 11491 Title: Nagios: Fix broken config reason displaying Component: Core & setup Level: 1 Class: Bug fix Version: 1.6.0p18 This issue is only affecting Checkmk installations that use the Nagios core. In case a configuration error occurs, the reason for this issue should be displayed in the console or the GUI like this: "When Validating Nagios configuration...ERROR: REASON". However, since release v1.6.0p4 the output of the config validation was not shown to the user. Instead this text was shown instead: "Validating Nagios configuration...ERROR: Configuration Error: local variable 'cmk' referenced before assignment"