Use crypto/rand.Read, not crypto.Reader.Read

The current code accidentally ignores partial reads, since it doesn't
check the return value of (io.Reader).Read.

What we actually want is io.ReadFull(rand.Reader, buf), which is
conveniently provided by rand.Read(buf).

Signed-off-by: edef <edef@edef.eu>

pkg/ip/link_linux.go

@@ -107,7 +107,7 @@ func makeVeth(name, vethPeerName string, mtu int, mac string, hostNS ns.NetNS) (
 // RandomVethName returns string "veth" with random prefix (hashed from entropy)
 func RandomVethName() (string, error) {
 	entropy := make([]byte, 4)
-	_, err := rand.Reader.Read(entropy)
+	_, err := rand.Read(entropy)
 	if err != nil {
 		return "", fmt.Errorf("failed to generate random veth name: %v", err)
 	}