Use latest version of storage-provisioner to work around kubernetes#7218

Also need to follow instructions here:
kubernetes#7218 (comment)

> After installing new version of storage-provisioner you need to edit
clusterrole:
> `kubectl edit clusterrole -n kube-system system:persistent-volume-provisioner`
> and add new permissions there

```
- apiGroups:
  - ""
  resources:
  - endpoints
  verbs:
  - get
  - list
  - watch
  - create
  - patch
  - update
```

deploy/addons/storage-provisioner/storage-provisioner.yaml.tmpl

@@ -51,7 +51,7 @@ spec:
   hostNetwork: true
   containers:
   - name: storage-provisioner
-    image: {{default "gcr.io/k8s-minikube" .ImageRepository}}/storage-provisioner{{.ExoticArch}}:v1.8.1
+    image: {{default "gcr.io/k8s-minikube" .ImageRepository}}/storage-provisioner{{.ExoticArch}}:latest
     command: ["/storage-provisioner"]
     imagePullPolicy: IfNotPresent
     volumeMounts: