enable nonamedreturns linter

Signed-off-by: Matthieu MOREL <matthieu.morel35@gmail.com>

pkg/ip/link_linux.go

@@ -67,38 +67,37 @@ func peerExists(name string) bool {
 	return true
 }
 
-func makeVeth(name, vethPeerName string, mtu int, mac string, hostNS ns.NetNS) (peerName string, veth netlink.Link, err error) {
+func makeVeth(name, vethPeerName string, mtu int, mac string, hostNS ns.NetNS) (string, netlink.Link, error) {
+	var peerName string
+	var veth netlink.Link
+	var err error
 	for i := 0; i < 10; i++ {
 		if vethPeerName != "" {
 			peerName = vethPeerName
 		} else {
 			peerName, err = RandomVethName()
 			if err != nil {
-				return
+				return peerName, nil, err
 			}
 		}
 
 		veth, err = makeVethPair(name, peerName, mtu, mac, hostNS)
 		switch {
 		case err == nil:
-			return
+			return peerName, veth, err
 
 		case os.IsExist(err):
 			if peerExists(peerName) && vethPeerName == "" {
 				continue
 			}
-			err = fmt.Errorf("container veth name provided (%v) already exists", name)
-			return
-
+			return peerName, veth, fmt.Errorf("container veth name provided (%v) already exists", name)
 		default:
-			err = fmt.Errorf("failed to make veth pair: %v", err)
-			return
+			return peerName, veth, fmt.Errorf("failed to make veth pair: %v", err)
 		}
 	}
 
 	// should really never be hit
-	err = fmt.Errorf("failed to find a unique veth name")
-	return
+	return peerName, nil, fmt.Errorf("failed to find a unique veth name")
 }
 
 // RandomVethName returns string "veth" with random prefix (hashed from entropy)