test: use reclaimPolicy Delete instead

Retain will make the condition check in pod_test.go failed.

Signed-off-by: Derek Su <derek.su@suse.com>

test/testdata/custom-path-pattern/storage-class.yaml

@@ -7,4 +7,4 @@ parameters:
   nodePath: /opt/local-path-provisioner
   pathPattern: "{{ .PVC.Namespace }}/{{ .PVC.Name }}"
 volumeBindingMode: WaitForFirstConsumer
-reclaimPolicy: Retain
+reclaimPolicy: Delete
\ No newline at end of file