Deletes this hub.

def close(self):
        """
        Deletes this hub.
        """

        for nio in self._nios:
            if nio:
                yield from nio.close()

        try:
            yield from Bridge.delete(self)
            log.info('Ethernet hub "{name}" [{id}] has been deleted'.format(name=self._name, id=self._id))
        except DynamipsError:
            log.debug("Could not properly delete Ethernet hub {}".format(self._name))
        if self._hypervisor and not self._hypervisor.devices:
            yield from self.hypervisor.stop()
            self._hypervisor = None
        return True