'Sets a metadata item, by key, for a server.
For a full list of available parameters, please refer to the official
API reference:
https://developer.openstack.org/api-ref/compute/#create-or-update-metadata-item'

def set_server_metadata_item(self, server_id, key, meta):

    post_body = json.dumps({'meta': meta})
    (resp, body) = self.put(('servers/%s/metadata/%s' % (server_id, key)), post_body)
    body = json.loads(body)
    self.validate_response(schema.set_show_server_metadata_item, resp, body)
    return rest_client.ResponseBody(resp, body)
