Fixed problem with error validation on AdminClient

    def _process(self, op, *args, **kwargs):

        header, value = op.build(*args, **kwargs)

        try:

            r = None

            with self:

                # update header

                self.update_header(header)

                # send message synchronously

                r, v = self.send(header, value)

            operations._check_status(r)

            return op.parse(r,v)

        except Exception as e:

            return op.onError(e)