Change apiversion for destination policies sample in bookinfo (istio#…

…4734)

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Change apiversion for destination policies sample in bookinfo

In Bookinfo sample, there is an example of definition of a DestinationPolicy (`/samples/bookinfo/kube/destination-policy-reviews.yaml`). 

When creating it into a Open Shift cluster using:

`oc create -f samples/bookinfo/kube/destination-policy-reviews.yaml`

it prompts the following error:

> Error from server (BadRequest): error when creating "samples/bookinfo/kube/destination-policy-reviews.yaml": the API version in the data (config.istio.io/v1beta1) does not match the expected API version (config.istio.io/v1alpha2)

Changing the DestinationPolicy apiVersion from `v1beta1` to `v1alpha2` just fix this issue.

samples/bookinfo/kube/destination-policy-reviews.yaml

@@ -1,4 +1,4 @@
-apiVersion: config.istio.io/v1beta1
+apiVersion: config.istio.io/v1alpha2
 kind: DestinationPolicy
 metadata:
   name: reviews-random