Longhorn: Upgrade from 1.8.1 to 1.9.0

Change-Id: I809890d3f73e85119c5f3d97e53856bd371c8c81
diff --git a/charts/longhorn/templates/storageclass.yaml b/charts/longhorn/templates/storageclass.yaml
index 884d38d..34723a4 100644
--- a/charts/longhorn/templates/storageclass.yaml
+++ b/charts/longhorn/templates/storageclass.yaml
@@ -15,7 +15,7 @@
     provisioner: driver.longhorn.io
     allowVolumeExpansion: true
     reclaimPolicy: "{{ .Values.persistence.reclaimPolicy }}"
-    volumeBindingMode: Immediate
+    volumeBindingMode: {{ .Values.persistence.volumeBindingMode | default "Immediate" }}
     parameters:
       numberOfReplicas: "{{ .Values.persistence.defaultClassReplicaCount }}"
       staleReplicaTimeout: "30"
@@ -55,3 +55,6 @@
       disableRevisionCounter: "{{ .Values.persistence.disableRevisionCounter }}"
       dataEngine: "{{ .Values.persistence.dataEngine }}"
       {{- end }}
+      {{- if .Values.persistence.backupTargetName }}
+      backupTargetName: "{{ .Values.persistence.backupTargetName }}"
+      {{- end }}