Checkmk Werk 11807: local check: Do not crash on negative timespans

ID: 11807 Title: local check: Do not crash on negative timespans Component: Checks & agents Level: 1 Class: Bug fix Version: 2.1.0i1 In case a host's time is running ahead of checkmk's server time, a cached local section will crash in the plugin. This is fixed now and a message will be generated.