fix test

Signed-off-by: Jan-Otto Kröpke <[email protected]>

tests.yaml

@@ -152,7 +152,7 @@ tests:
         severity: critical
       exp_annotations:
         summary: "PersistentVolume is filling up."
-        description: 'The PersistentVolume claimed by somepvc in Namespace monitoring is only 1.263% free.'
+        description: 'The PersistentVolume claimed by somepvc in Namespace monitoring on Cluster  only is only 1.263% free.'
         runbook_url: https://github.com/kubernetes-monitoring/kubernetes-mixin/tree/master/runbook.md#alert-name-kubepersistentvolumefillingup
 
 # Block volume mounts can report 0 for the kubelet_volume_stats_used_bytes metric but it shouldn't trigger the KubePersistentVolumeFillingUp alert.