Activate the hwvtep

        Args:
            name (str): overlay_gateway name
            callback (function): A function executed upon completion of the
                 method.

        Returns:
           Return value of `callback`.

        Raises:
            None

def hwvtep_activate_hwvtep(self, **kwargs):
        """
        Activate the hwvtep

        Args:
            name (str): overlay_gateway name
            callback (function): A function executed upon completion of the
                 method.

        Returns:
           Return value of `callback`.

        Raises:
            None
        """
        name = kwargs.pop('name')
        name_args = dict(name=name)
        method_name = 'overlay_gateway_activate'
        method_class = self._brocade_tunnels
        gw_attr = getattr(method_class, method_name)
        config = gw_attr(**name_args)
        output = self._callback(config)
        return output