In this change, we add admin policy check for metadata keys "__affinity_same_host" and "__affinity_different_host". These keys are added an constants, allowing for the addition of other admin only keys if necessary in future changes. This change allows for the affinity filter spec[1] implementation without the additional changes necessary in the metadata spec[2]. Bumps microversion to 2.68. [1] https://specs.openstack.org/openstack/manila-specs/specs/xena/affinity-antiaffinity-filter.html [2] https://specs.openstack.org/openstack/manila-specs/specs/wallaby/metadata-for-share-resources.html Partially-Implements: metadata-for-share-resources Change-Id: I6ee02cb66727a3c2b425fad1d9d1245d4e9c1b24