cgpt: create: Don't modify existing IGNOREME headers

Respect any existing IGNOREME signatures and do not attempt to make any
modifications until a user has explicitly removed this flag via cgpt
legacy or other method.

BRANCH=None
BUG=chromium:948742
TEST=chromeos-install on veyron_minnie with 4.19 kernel

Change-Id: I110a95ee0c136ebbe2274139deebcaacde712e80
Signed-off-by: Ryan Case <ryandcase@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1572440
Commit-Ready: Ryan Case <ryandcase@google.com>
Tested-by: Ryan Case <ryandcase@google.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>
1 file changed