check ErrorNotFound in netlink.go to fix cross build error

pkg/proxy/ipvs/netlink_linux.go

@@ -57,7 +57,7 @@ func (h *netlinkHandle) EnsureAddressBind(address, devName string) (exist bool,
 	return false, nil
 }
 
-// UnbindAddress unbind address from the interface
+// UnbindAddress makes sure IP address is unbound from the network interface.
 func (h *netlinkHandle) UnbindAddress(address, devName string) error {
 	dev, err := h.LinkByName(devName)
 	if err != nil {
@@ -68,7 +68,9 @@ func (h *netlinkHandle) UnbindAddress(address, devName string) error {
 		return fmt.Errorf("error parse ip address: %s", address)
 	}
 	if err := h.AddrDel(dev, &netlink.Addr{IPNet: netlink.NewIPNet(addr)}); err != nil {
-		return fmt.Errorf("error unbind address: %s from interface: %s, err: %v", address, devName, err)
+		if err != unix.ENXIO {
+			return fmt.Errorf("error unbind address: %s from interface: %s, err: %v", address, devName, err)
+		}
 	}
 	return nil
 }

pkg/proxy/ipvs/proxier.go

@@ -51,8 +51,6 @@ import (
 	utilipvs "k8s.io/kubernetes/pkg/util/ipvs"
 	utilsysctl "k8s.io/kubernetes/pkg/util/sysctl"
 	utilexec "k8s.io/utils/exec"
-
-	"golang.org/x/sys/unix"
 )
 
 const (
@@ -1705,7 +1703,7 @@ func (proxier *Proxier) cleanLegacyService(atciveServices map[string]bool, curre
 	for _, addr := range unbindIPAddr.UnsortedList() {
 		err := proxier.netlinkHandle.UnbindAddress(addr, DefaultDummyDevice)
 		// Ignore no such address error when try to unbind address
-		if err != nil && err != unix.ENXIO {
+		if err != nil {
 			glog.Errorf("Failed to unbind service addr %s from dummy interface %s: %v", addr, DefaultDummyDevice, err)
 		}
 	}