https://developer.openstack.org/api-ref/block-storage/v3/index.html#list-snapshots-and-details
1. updated_at is missing in the response fields of show-snapshot
and list-snapshots
2. id's description is "The UUID of the volume transfer.", which
is incorrect.
3. volume_id's description is "The UUID of the volume.", which is
not very accurate.
4. os-extended-snapshot-attributes:progress is something like '100%',
so it should be string, not integer
5. response fields of show-snapshot-metadata is incorrect.
6. metadata is missing in the response example of update-snapshot
7. snapshots_links is missing in the response of list-snapshot
Change-Id: I0f6994c2d2dc27d3d594acdd460e27c338f86a2c
5c82ba8b4b