Fix go vet error

stderr is a bytes.Buffer, but the String() method has a pointer
receiver, so stderr does not satisify the Stringer interface
and can't be used for a %s argument.  Make stderr a *bytes.Buffer
instead.

Test: go vet ./android
Change-Id: I994402cb954946279375c9d447ad3854380381cc

android/bazel_handler.go

@@ -188,8 +188,8 @@ func (context *bazelContext) issueBazelCommand(command string, labels []string,
 	bazelCmd.Dir = context.workspaceDir
 	bazelCmd.Env = append(os.Environ(), "HOME="+context.homeDir, pwdPrefix())
 
-	var stderr bytes.Buffer
-	bazelCmd.Stderr = &stderr
+	stderr := &bytes.Buffer{}
+	bazelCmd.Stderr = stderr
 
 	if output, err := bazelCmd.Output(); err != nil {
 		return "", fmt.Errorf("bazel command failed. command: [%s], error [%s]", bazelCmd, stderr)