kernel build: use %U+1 for dm-verity booting

bin/cros_make_image_bootable

 #!/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.
 #
 # Script which ensures that a given image has an up-to-date
 # kernel partition, rootfs integrity hashes, and legacy bootloader configs.
 
 # --- BEGIN COMMON.SH BOILERPLATE ---
@@ skipping 125 matching lines @@
   local statefs="${2-$FLAGS_statefulfs_mountpoint}"
   local espfs="${3-$FLAGS_espfs_mountpoint}"
   "${SCRIPTS_DIR}/mount_gpt_image.sh" \
     -u -r "${rootfs}" -s "${statefs}" -e "${espfs}"
 }
 
 make_image_bootable() {
   local image="$1"
   local use_dev_keys=
 
+  # Default to non-verified, non-UUID boot unless verified.
+  # Long term we want root=PARTUUID=uuid+1.
   cros_root=/dev/sd%D%P
   if [[ "${FLAGS_arch}" = "arm" ]]; then
     cros_root='/dev/${devname}${rootpart}'
   fi
   if [[ ${FLAGS_enable_rootfs_verification} -eq ${FLAGS_TRUE} ]]; then
     cros_root=/dev/dm-0
   fi
 
   trap "mount_gpt_cleanup" EXIT
   "${SCRIPTS_DIR}/mount_gpt_image.sh" --from "$(dirname "${image}")" \
@@ skipping 142 matching lines @@
 mkdir -p ${FLAGS_espfs_mountpoint}
 
 make_image_bootable "${IMAGE}"
 verify_image_rootfs "${IMAGE}"
 
 if [ ${FLAGS_cleanup_dirs} -eq ${FLAGS_TRUE} ]; then
   rmdir ${FLAGS_rootfs_mountpoint}
   rmdir ${FLAGS_statefulfs_mountpoint}
   rmdir ${FLAGS_espfs_mountpoint}
 fi