Check_MK Werk 5799: Availability: Fixed error in duration computation when merging identical states

ID: 5799 Title: Availability: Fixed error in duration computation when merging identical states Component: Checks & agents Level: 1 Class: Bug fix Version: 1.6.0i1 This error appears when the availability timeline is not fully connect, e.g. if it is split by a service period. The computation error itself seems no big issue, since this incorrect computed value wasn't evaluated, anyway.