Filter out unknown chargegroup names
We got unknown values in the db that affected the grafana plots.https://monit-grafana.cern.ch/d/8f4TgzF7z/driverab-new-cern-openstack-overview-test?orgId=3&viewPanel=49
We got unknown values in the db that affected the grafana plots.https://monit-grafana.cern.ch/d/8f4TgzF7z/driverab-new-cern-openstack-overview-test?orgId=3&viewPanel=49