Get the number of names in a namespace
        Return {'status': true, 'count': count} on success
        Return {'error': ...} on error

def rpc_get_num_names_in_namespace( self, namespace_id, **con_info ):
        """
        Get the number of names in a namespace
        Return {'status': true, 'count': count} on success
        Return {'error': ...} on error
        """
        if not check_namespace(namespace_id):
            return {'error': 'Invalid name or namespace', 'http_status': 400}

        db = get_db_state(self.working_dir)
        num_names = db.get_num_names_in_namespace( namespace_id )
        db.close()

        return self.success_response( {'count': num_names} )