Updating nagios cluster role for rbd monitoring

This patchset is required for the patch set https://review.opendev.org/#/c/737629.
The kuberntes python api requires these permissions, for this script to work properly.

Change-Id: I69f2ca40ab6068295a4cb2d85073183ca348af1e

nagios/templates/deployment.yaml

@@ -33,6 +33,9 @@ rules:
       - services
       - endpoints
       - pods
+      - pods/exec
+      - persistentvolumes
+      - persistentvolumeclaims
     verbs:
       - get
       - list