'Update metadata items for a server
http://localhost/api/nova/servers/1/metadata'

@rest_utils.ajax()
def patch(self, request, server_id):

    updated = request.DATA['updated']
    removed = request.DATA['removed']
    if updated:
        api.nova.server_metadata_update(request, server_id, updated)
    if removed:
        api.nova.server_metadata_delete(request, server_id, removed)
