Update policy.json example for grizzly vol changes

As noted in the bug report, new extension was added for
volumes. We don't currently refer to policy.json outside
this example, so the fix is just to update the example
with the new lines.

fixes bug 1111099

Change-Id: I6a64959da4308faa57b4b6985b91eacaf6d9dc09
Merge "Update policy.json example for grizzly vol changes"