[wpr-go] Include stderr in error msg

web_page_replay_go/src/webpagereplay/adb_cert_installer.go

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package webpagereplay
 
 import (
         "bytes"
         "fmt"
         "io/ioutil"
@@ skipping 34 matching lines @@
 // Runs the adb shell command.
 func (i *Installer) adbShell(args ...string) error {
         shellArgs := append([]string{"shell"}, args...)
         return i.adb(shellArgs...)
 }
 
 // The issuer hash is used as filename for the installed cert.
 func getIssuerHashFileName(certPath string) (string, error) {
         cmd := exec.Command("openssl", "x509", "-in", certPath, "-issuer_hash_old", "-noout")
         var out bytes.Buffer
+        var stderr bytes.Buffer
         cmd.Stdout = &out
+        cmd.Stderr = &stderr
         err := cmd.Run()
         if err != nil {
-                return "", err
+                return "", fmt.Errorf("%v : %s", err, stderr.String())
         }
         fmt.Print(out.String())
         return strings.Trim(out.String(), "\r\n") + ".0", nil
 }
 
 // Formats the cert and returns the formatted cert.
 func formatCert(certPath string) (string, error) {
         cmd := exec.Command("openssl", "x509", "-inform", "PEM", "-text", "-in", certPath)
         var out bytes.Buffer
         cmd.Stdout = &out
@@ skipping 43 matching lines @@
 func (i *Installer) AdbUninstallRoot() error {
         var err error
         if err = i.adbShell("umount", androidSystemCertDir); err != nil {
                 return err
         }
         if err = i.adbShell("rm", "-r", androidTempCertDir); err != nil {
                 return err
         }
         return nil
 }