Revert "Use netlink.SetPromiscOn instead of iproute2 command"

vendor/github.com/vishvananda/netns/netns_unspecified.go

@@ -1,35 +0,0 @@
-// +build !linux
-
-package netns
-
-import (
-	"errors"
-)
-
-var (
-	ErrNotImplemented = errors.New("not implemented")
-)
-
-func Set(ns NsHandle) (err error) {
-	return ErrNotImplemented
-}
-
-func New() (ns NsHandle, err error) {
-	return -1, ErrNotImplemented
-}
-
-func Get() (NsHandle, error) {
-	return -1, ErrNotImplemented
-}
-
-func GetFromName(name string) (NsHandle, error) {
-	return -1, ErrNotImplemented
-}
-
-func GetFromPid(pid int) (NsHandle, error) {
-	return -1, ErrNotImplemented
-}
-
-func GetFromDocker(id string) (NsHandle, error) {
-	return -1, ErrNotImplemented
-}