factory_reset: Fix cutoff script location.

The battery cutoff scripts have been changed both folder name and main
script file name (from battery_cutoff.sh to cutoff.sh) so we have to
also change installer code.

The original code also has a typo - should be DIR, not SCRIPT.

BUG=chromium:577601
TEST=build_image factory_install; boot to menu; action 'r'.

Change-Id: I7318a9798f59ffa48d164dfe0e96b1cb05e03bc8
Reviewed-on: https://chromium-review.googlesource.com/410522
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Chun-Tsen Kuo <chuntsen@chromium.org>
diff --git a/factory_reset.sh b/factory_reset.sh
index 8f2583b..29a6cc6 100644
--- a/factory_reset.sh
+++ b/factory_reset.sh
@@ -18,7 +18,7 @@
 
 # CUTOFF_DIR is provided from platform/factory/sh/cutoff, repacked by ebuild.
 CUTOFF_DIR="/usr/share/cutoff"
-CUTOFF_SCRIPT="${CUTOFF_SCRIPT}/battery_cutoff.sh"
+CUTOFF_SCRIPT="${CUTOFF_DIR}/cutoff.sh"
 INFORM_SHOPFLOOR_SCRIPT="${CUTOFF_DIR}/inform_shopfloor.sh"
 
 usage() {