Don't install glance default policy
Don't install glance default policy

With Glance defining default policies in code, it's no longer necessary
to install policy.json from the repo.

Change-Id: I9f9160f5a2bf9fd77fb3807e12de219b7a49952d
Depends-On: https://review.opendev.org/693129

openstack-dev/devstack,nawawi/openstack,openstack-dev/devstack,nawawi/openstack