libct/system: rm Execv

This is not used since commit dac41717.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

libcontainer/system/linux.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"os/exec"
 	"strconv"
 	"syscall"
 	"unsafe"
@@ -36,14 +35,6 @@ func (p ParentDeathSignal) Set() error {
 	return SetParentDeathSignal(uintptr(p))
 }
 
-func Execv(cmd string, args []string, env []string) error {
-	name, err := exec.LookPath(cmd)
-	if err != nil {
-		return err
-	}
-	return Exec(name, args, env)
-}
-
 func Exec(cmd string, args []string, env []string) error {
 	for {
 		err := unix.Exec(cmd, args, env)