scripts: remove unused variables

Remove unused variables from mod_image_for_recovery.sh. No functional
change.

BUG=none
TEST=mod_image_for_recovery.sh still works

Change-Id: Idfceba65b82d54eff6f2931e4c057350c9a3a22e
Reviewed-on: https://chromium-review.googlesource.com/1705919
Tested-by: Thiemo Nagel <tnagel@chromium.org>
Commit-Ready: Thiemo Nagel <tnagel@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/mod_image_for_recovery.sh b/mod_image_for_recovery.sh
index 2d3c53e..3be2271 100755
--- a/mod_image_for_recovery.sh
+++ b/mod_image_for_recovery.sh
@@ -104,10 +104,6 @@
 create_recovery_kernel_image() {
   local sysroot="$FACTORY_ROOT"
   local vmlinuz="$sysroot/boot/vmlinuz"
-  local partition_num_root_a=$(get_image_partition_number "${RECOVERY_IMAGE}" \
-    "ROOT-A")
-  local root_offset=$(partoffset "${RECOVERY_IMAGE}" "${partition_num_root_a}")
-  local root_size=$(partsize "${RECOVERY_IMAGE}" "${partition_num_root_a}")
 
   local enable_rootfs_verification_flag=--noenable_rootfs_verification
   if grep -q enable_rootfs_verification "${IMAGE_DIR}/boot.desc"; then