futility: updater: Fix build failure due to fts.

`fts` in old branches cannot use 64 bit file offset.

BUG=chromium:923934
TEST=emerge-gru vboot_reference

Change-Id: I0184847b19e470c86aac9a7cbb2d7b1f3cbf653d
Reviewed-on: https://chromium-review.googlesource.com/c/1426260
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Commit-Queue: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Trybot-Ready: Hung-Te Lin <hungte@chromium.org>
1 file changed