Check_MK Werk 6654: Bug fixing in predictive levels

ID: 6654 Title: Bug fixing in predictive levels Component: Core & setup Level: 1 Class: Bug fix Version: 1.6.0i1 Predictive levels calculations suffered from some buggy behaviors under certain configuration conditions like: no predictions after 22:30, inhability to fetch data despite months of available perf data, prediction pointer offset by an hour in timezones with dayligth savings time.