detachables: Disable Network Boot Option

BUG=b:65595963
BRANCH=None
TEST=enabled Dev mode, reboot, select developer options &
     make sure Network Boot doesn't appear in menu.

Change-Id: I30953d037740259b06011ecb141d508db114b79e
Signed-off-by: Shelley Chen <shchen@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/664298
Reviewed-by: Julius Werner <jwerner@chromium.org>
1 file changed