remove duplicate persistent_volumes_enabled parameter in k8s-cluster.yml

inventory/sample/group_vars/k8s-cluster/k8s-cluster.yml

@@ -176,8 +176,6 @@ podsecuritypolicy_enabled: false
 volume_cross_zone_attachment: false
 # Add Persistent Volumes Storage Class for corresponding cloud provider ( OpenStack is only supported now )
 persistent_volumes_enabled: false
-# Add Persistent Volumes Storage Class for corresponding cloud provider ( OpenStack is only supported now )
-persistent_volumes_enabled: false
 
 ## Container Engine Acceleration
 ## Enable container accelertion feature, for example use gpu acceleration in containers