This fixes a build break in mod_image_for_test.sh

mod_image_for_test.sh

 #!/bin/bash
 
 # Copyright (c) 2009 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.
 
 # Script to modify a keyfob-based chromeos system image for testability.
 
 # --- BEGIN COMMON.SH BOILERPLATE ---
 # Load common CrOS utilities.  Inside the chroot this file is installed in
@@ skipping 172 matching lines @@
 else
   echo "Modifying image ${FLAGS_image} for test..."
 fi
 
 set -e
 
 IMAGE_DIR=$(dirname "$FLAGS_image")
 IMAGE_NAME="$(basename "$FLAGS_image")"
 ROOT_FS_DIR="$IMAGE_DIR/rootfs"
 STATEFUL_DIR="$IMAGE_DIR/stateful_partition"
-SCRIPTS_DIR=${SCRIPT_ROOT}
 DEV_USER="chronos"
 
 trap cleanup EXIT
 
 # Mounts gpt image and sets up var, /usr/local and symlinks.
 "$SCRIPTS_DIR/mount_gpt_image.sh" -i "$IMAGE_NAME" -f "$IMAGE_DIR" \
   -r "$ROOT_FS_DIR" -s "$STATEFUL_DIR"
 
 if [ ${FLAGS_factory_install} -eq ${FLAGS_TRUE} ]; then
   # We don't want to emerge test packages on factory install, otherwise we run
@@ skipping 42 matching lines @@
 cleanup
 
 # Now make it bootable with the flags from build_image
 "${SCRIPTS_DIR}/bin/cros_make_image_bootable" "$(dirname "${FLAGS_image}")" \
                                             $(basename "${FLAGS_image}")
 
 print_time_elapsed
 
 trap - EXIT