Upgrade: Longhorn from 1.5.2 to 1.6.4

Change-Id: I8cdc3c0a07133f00442b496800ccc30e2c1dad61
diff --git a/charts/longhorn/templates/network-policies/backing-image-data-source-network-policy.yaml b/charts/longhorn/templates/network-policies/backing-image-data-source-network-policy.yaml
index cc91054..7204d63 100644
--- a/charts/longhorn/templates/network-policies/backing-image-data-source-network-policy.yaml
+++ b/charts/longhorn/templates/network-policies/backing-image-data-source-network-policy.yaml
@@ -3,7 +3,7 @@
 kind: NetworkPolicy
 metadata:
   name: backing-image-data-source
-  namespace: longhorn-system
+  namespace: {{ include "release_namespace" . }}
 spec:
   podSelector:
     matchLabels: