'Clear the VF rate parameter specified in rate_type
Clear the rate configuration from VF by setting it to 0.
@param pci_slot: VF PCI slot
@param rate_type: rate to clear (\'rate\', \'min_tx_rate\')'

def _clear_rate(self, pci_slot, rate_type):

    embedded_switch = self.pci_slot_map.get(pci_slot)
    if embedded_switch:
        if (embedded_switch.get_pci_device(pci_slot) is None):
            embedded_switch.set_device_rate(pci_slot, rate_type, 0)
        else:
            LOG.warning(_LW("VF    with    PCI    slot    %(pci_slot)s    is    already    assigned;    skipping    reset    for    '%(rate_type)s'    device    configuration    parameter"), {'pci_slot': pci_slot, 'rate_type': rate_type})
    else:
        LOG.error(_LE('PCI    slot    %(pci_slot)s    has    no    mapping    to    Embedded    Switch;    skipping'), {'pci_slot': pci_slot})
