crypto/tls: consistently use %v for error formatting

We should keep a consistent way of formatting errors
in this file.

Fixes #34848

Change-Id: Ibb75908504f381fccab0281a42e788ef8c716b6f
Reviewed-on: https://go-review.googlesource.com/c/go/+/200679
Run-TryBot: Johan Brandhorst <johan.brandhorst@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

src/crypto/tls/generate_cert.go

@@ -78,7 +78,7 @@ func main() {
 		log.Fatalf("Unrecognized elliptic curve: %q", *ecdsaCurve)
 	}
 	if err != nil {
-		log.Fatalf("Failed to generate private key: %s", err)
+		log.Fatalf("Failed to generate private key: %v", err)
 	}
 
 	var notBefore time.Time
@@ -87,7 +87,7 @@ func main() {
 	} else {
 		notBefore, err = time.Parse("Jan 2 15:04:05 2006", *validFrom)
 		if err != nil {
-			log.Fatalf("Failed to parse creation date: %s", err)
+			log.Fatalf("Failed to parse creation date: %v", err)
 		}
 	}
 
@@ -96,7 +96,7 @@ func main() {
 	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
 	serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
 	if err != nil {
-		log.Fatalf("Failed to generate serial number: %s", err)
+		log.Fatalf("Failed to generate serial number: %v", err)
 	}
 
 	template := x509.Certificate{
@@ -128,24 +128,24 @@ func main() {
 
 	derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv)
 	if err != nil {
-		log.Fatalf("Failed to create certificate: %s", err)
+		log.Fatalf("Failed to create certificate: %v", err)
 	}
 
 	certOut, err := os.Create("cert.pem")
 	if err != nil {
-		log.Fatalf("Failed to open cert.pem for writing: %s", err)
+		log.Fatalf("Failed to open cert.pem for writing: %v", err)
 	}
 	if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
-		log.Fatalf("Failed to write data to cert.pem: %s", err)
+		log.Fatalf("Failed to write data to cert.pem: %v", err)
 	}
 	if err := certOut.Close(); err != nil {
-		log.Fatalf("Error closing cert.pem: %s", err)
+		log.Fatalf("Error closing cert.pem: %v", err)
 	}
 	log.Print("wrote cert.pem\n")
 
 	keyOut, err := os.OpenFile("key.pem", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
 	if err != nil {
-		log.Fatalf("Failed to open key.pem for writing:", err)
+		log.Fatalf("Failed to open key.pem for writing: %v", err)
 		return
 	}
 	privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
@@ -153,10 +153,10 @@ func main() {
 		log.Fatalf("Unable to marshal private key: %v", err)
 	}
 	if err := pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
-		log.Fatalf("Failed to write data to key.pem: %s", err)
+		log.Fatalf("Failed to write data to key.pem: %v", err)
 	}
 	if err := keyOut.Close(); err != nil {
-		log.Fatalf("Error closing key.pem: %s", err)
+		log.Fatalf("Error closing key.pem: %v", err)
 	}
 	log.Print("wrote key.pem\n")
 }