Have ipam.ExecDel set CNI_COMMAND to DEL

plugins/main/macvlan/macvlan.go

@@ -19,7 +19,6 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"os"
 	"runtime"
 
 	"github.com/j-keck/arping"
@@ -227,9 +226,7 @@ func cmdAdd(args *skel.CmdArgs) error {
 		// Invoke ipam del if err to avoid ip leak
 		defer func() {
 			if err != nil {
-				os.Setenv("CNI_COMMAND", "DEL")
 				ipam.ExecDel(n.IPAM.Type, args.StdinData)
-				os.Setenv("CNI_COMMAND", "ADD")
 			}
 		}()