# File lib/fog/openstack/requests/compute/update_meta.rb, line 7
        def update_meta(collection_name, parent_id, key, value)
          request(
            :body     => MultiJson.encode({ 'meta' => { key => value }}),
            :expects  => 200,
            :method   => 'PUT',
            :path     => "#{collection_name}/#{parent_id}/metadata/#{key}"
          )
        end