mount_gpt_image.sh: Fix path to include chromeos-common.sh

mount_gpt_image.sh can be run outside of the chroot. In that case it
will include file from the source code, not the installed location.
Reflect the code change location.

BUG=b:72749926
TEST=tryjob novato.

Change-Id: I6ca9d97ec1c3db5d91f048f459aa045a41437ab3
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1042852
Tested-by: Gwendal Grignou <gwendal@google.com>
Trybot-Ready: Gwendal Grignou <gwendal@google.com>
Reviewed-by: Nicolas Norvez <norvez@chromium.org>
Commit-Queue: Hung-Te Lin <hungte@chromium.org>
diff --git a/mount_gpt_image.sh b/mount_gpt_image.sh
index 4ce81c0..503bc7c 100755
--- a/mount_gpt_image.sh
+++ b/mount_gpt_image.sh
@@ -13,8 +13,8 @@
 . "${SCRIPT_ROOT}/build_library/filesystem_util.sh" || exit 1
 . "${SCRIPT_ROOT}/build_library/disk_layout_util.sh" || exit 1
 
-if [[ $INSIDE_CHROOT -ne 1 ]]; then
-  INSTALL_ROOT="$SRC_ROOT/platform2/installer/share"
+if [[ ${INSIDE_CHROOT} -ne 1 ]]; then
+  INSTALL_ROOT="${SRC_ROOT}/platform2/chromeos-common-script/share"
 else
   INSTALL_ROOT=/usr/share/misc
 fi