BUG=chromium-os:23229
TEST=ran this against a ToT alex img, image_to_usb, boots, installs, works
Change-Id: Ia1e589a8b920332c1a247986e6bbc3cad17ed751
Reviewed-on: https://gerrit.chromium.org/gerrit/14650
Commit-Ready: Jim Hebert <jimhebert@chromium.org>
Tested-by: Jim Hebert <jimhebert@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>