Check_MK Werk 7243: Fixed wrong sorting of perfometers when some services have no metrics

ID: 7243 Title: Fixed wrong sorting of perfometers when some services have no metrics Component: Multisite Level: 1 Class: Bug fix Version: 1.6.0i1 When sorting a list of services by the perfometer column, this did not work correctly in case there were services in this list that have no metrics at all.