Always enter BROKEN screen in non-manual recovery, even in dev mode

Previously, non-manual recovery behavior would depend on the developer
mode switch: in normal mode it would get stuck at the BROKEN screen, but
in developer mode it would proceed exactly like manual recovery. This
behavior was mostly just confusing to people and it seems that we have
no real use case for it anymore. Remove the developer mode special case
so that non-manual recovery will always go to the BROKEN screen from now
on.

BRANCH=scarlet?
BUG=None
TEST=make runtests, verified manually on Scarlet and Kevin

Change-Id: Iaf33f82d7cb709a5ee309c08d1ad3015859738b3
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/924458
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
3 files changed