Remove policy.json file

The policy file is just a dup of what's already in the distro
packages.  Until the cookbooks/chef support a policy type resource
duping them does not make sense and causes churn to keep in sync
with base openstack code.

Change-Id: Ib09d5efdf3927a381501eebd78d5c4db5133f057
Implements: blueprint remove-policy-templates
Closes-Bug: #1324187