Checkmk Werk 13014: Fix agent proxmox bug if duration is more than 24 hours

ID: 13014 Title: Fix agent proxmox bug if duration is more than 24 hours Component: Checks & agents Level: 1 Class: Bug fix Version: 2.2.0i1 Fix a bug if duration string is more than 24 hours CMK-9146 In a rare occasion if the backup takes more than 24 hours the standard datetime string parsing fails. So the manual parsing and feeding bits to timedelta object solves the problem