set_chronos_password.sh: Add missing sudo while grepping the contents of shadow on root fs.

scripts/image_signing/set_chronos_password.sh

 #!/bin/bash
 
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Customizes a Chrome OS release image by setting the chronos user password.
 
 # Usage: ./set_chronos_password.sh <image.bin> <chronos_password>
 
 # Load common constants and variables.
 . "$(dirname "$0")/common.sh"
 
 change_chronos_password() {
   local rootfs=$1
   local password=$2
   echo "Changing chronos password to '$password'..."
   local crypted_password="$(echo $password | openssl passwd -1 -stdin)"
   local temp_shadow="$rootfs/etc/tempshadow"
   echo "chronos:$crypted_password:14500:0:99999::::" \
     | sudo tee "$temp_shadow" > /dev/null
-  grep -Ev ^chronos: "$rootfs/etc/shadow" \
+  sudo grep -Ev ^chronos: "$rootfs/etc/shadow" \
     | sudo tee -a "$temp_shadow" > /dev/null
   sudo mv -f "$temp_shadow" "$rootfs/etc/shadow"
 }
 
 main() {
   set -e
 
   local image=$1
   local chronos_password=$2
   if [ $# -ne 2 ]; then
     echo "Usage: $PROG <image.bin> <chronos_password>"
     exit 1
   fi
 
   local rootfs=$(mktemp -d)
   mount_image_partition "$image" 3 "$rootfs"
   trap "sudo umount -d $rootfs; rm -rf $rootfs" EXIT
   change_chronos_password "$rootfs" "$chronos_password"
   touch "$image"  # Updates the image modification time.
   echo "Done."
 }
 
 main $@