Add presubmit for kernel config/code changes

We don't allow kernel configs to be changed at the same time as code,
and to avoid having to comment on it on code review, add a presubmit
hook to check for it.

BUG=chromium-os:34143
TEST=run new unit test

Change-Id: Ia8e824d79235c1913276e8b9b6cca659943ab85d
Reviewed-on: https://gerrit.chromium.org/gerrit/32187
Commit-Ready: Olof Johansson <olofj@chromium.org>
Tested-by: Olof Johansson <olofj@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
2 files changed