Checkmk Werk 13162: check_mk_active: fix "AttributeError: 'NoneType' object has no attribute 'split'

ID: 13162 Title: check_mk_active: fix "AttributeError: 'NoneType' object has no attribute 'split' Component: Checks & agents Level: 1 Class: Bug fix Version: 2.1.0i1 This werk fixes the following issue with the check_mk_active: - When the option warn/crit-age-oldest or warn/crit-age-newest was used the following error could occur: "AttributeError: 'NoneType' object has no attribute 'split'"