force using local image_common

BUG=none
TEST=./make_factory_package.sh ...
Change-Id: I73c41c66228f269e4958b496ee1b73e3fe0fc9b0
Reviewed-on: http://gerrit.chromium.org/gerrit/7321
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
diff --git a/make_factory_package.sh b/make_factory_package.sh
index 99b0812..8243062 100755
--- a/make_factory_package.sh
+++ b/make_factory_package.sh
@@ -39,7 +39,7 @@
   die "Unable to load /usr/lib/installer/chromeos-common.sh"
 
 # Load functions designed for image processing
-. "${SCRIPT_ROOT}/lib/cros_image_common.sh" ||
+. "$(dirname $(readlink -f $0))/lib/cros_image_common.sh" ||
   die "Cannot load required library: lib/cros_image_common.sh; Abort."
 
 SCRIPT="$0"