'Delete a network interface access configuration from a node.
:keyword  node: The existing target Node (instance) for the request.
:type     node: ``Node``
:keyword  name: Name of the access config.
:type     name: ``str``
:keyword  nic: Name of the network interface.
:type     nic: ``str``
:return: True if successful
:rtype:  ``bool``'

def ex_delete_access_config(self, node, name, nic):

    if (not isinstance(node, Node)):
        raise ValueError('Must    specify    a    valid    libcloud    node    object.')
    node_name = node.name
    zone_name = node.extra['zone'].name
    params = {'accessConfig': name, 'networkInterface': nic}
    request = ('/zones/%s/instances/%s/deleteAccessConfig' % (zone_name, node_name))
    self.connection.async_request(request, method='POST', params=params)
    return True
