nic.go
func (c *Client) DeleteNic(dcid, srvid, nicid string) (*http.Header, error) {
	url := nicPath(dcid, srvid, nicid)
	ret := &http.Header{}
	err := c.client.Delete(url, ret, http.StatusAccepted)
	return ret, err
}
func (c *Client) DeleteNic(dcid, srvid, nicid string) (*http.Header, error) {
	url := nicPath(dcid, srvid, nicid)
	ret := &http.Header{}
	err := c.client.Delete(url, ret, http.StatusAccepted)
	return ret, err
}
// DeleteNic deletes the nic where id=nicid and returns a Resp struct