[stable/rethinkdb] Implement storageClass (helm#21750)

* [stable/rethinkdb] Fixed storageClass

The cluster.persistentVolume.storageClass was never used and would never
properly populate the volumeClaimTemplate.

This also adds the convention that "-" will set the null storage class
(as this is a pretty common convention).

Signed-off-by: Eric Stokes <fernferret@gmail.com>

* bumped chart version

Signed-off-by: Eric Stokes <fernferret@gmail.com>
Signed-off-by: Miguel Mingorance <miguel.mingorance@deliveryhero.com>

Author: fernferret

stable/rethinkdb/Chart.yaml

@@ -1,7 +1,7 @@
 apiVersion: v1
 name: rethinkdb
 description: The open-source database for the realtime web
-version: 1.1.0
+version: 1.1.1
 appVersion: 0.1.0
 keywords:
 - rethinkdb

stable/rethinkdb/templates/rethinkdb-cluster-stateful-set.yaml

@@ -99,6 +99,13 @@ spec:
       {{- range .Values.cluster.persistentVolume.accessModes }}
         - {{ . | quote }}
       {{- end }}
+      {{- if .Values.cluster.persistentVolume.storageClass }}
+      {{- if (eq "-" .Values.cluster.persistentVolume.storageClass) }}
+      storageClassName: ""
+      {{- else }}
+      storageClassName: "{{ .Values.cluster.persistentVolume.storageClass }}"
+      {{- end }}
+      {{- end }}
       resources:
         requests:
           storage: {{ .Values.cluster.persistentVolume.size | quote }}