Reland "vboot/sign_official_build: re-sign miniOS partitions"
Reland "vboot/sign_official_build: re-sign miniOS partitions"

This is a reland of 43325cb9b2568c4a03c849f3474fcee8de3ae893

Looks like this was reverted incorrectly in CL:3044633, culprit
turned out to be an unrelated flake (see b/194293181).

Original change's description:
> vboot/sign_official_build: re-sign miniOS partitions
>
> sign_official_build.sh needs to be taught how to re-sign miniOS
> partitions, depending on whether the particular image at hand
> contains them or not.
>
> BUG=b:188121855
> TEST=make clean && make runtests
> BRANCH=none
>
> Cq-Depend: chromium:3027786
> Signed-off-by: Joel Kitching <kitching@google.com>
> Change-Id: Iaf847e14588011dd0fea6b59405091ae36ef038f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2989640
> Tested-by: Joel Kitching <c2feea8c1334a0d339e816ae4c7c9ecfa9b30a91@chromium.org>
> Reviewed-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>
> Commit-Queue: Joel Kitching <c2feea8c1334a0d339e816ae4c7c9ecfa9b30a91@chromium.org>

Bug: b:188121855
Signed-off-by: Julius Werner <4d12f06cff3725783b352157673a720bc67c4afe@google.com>
Change-Id: I2e29a6e85f7d41ad365365ffb7e694f0c291d4f3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/3046439
Reviewed-by: Sergey Frolov <ad5991b2498127a66ef4f73a82731dc18d7463eb@google.com>
Reviewed-by: Joel Kitching <c2feea8c1334a0d339e816ae4c7c9ecfa9b30a91@chromium.org>
Reviewed-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>
Tested-by: Julius Werner <4d12f06cff3725783b352157673a720bc67c4afe@chromium.org>
Bot-Commit: Rubber Stamper <d516c4cc2192058ab8dae3d306acbdaf2ce6574f@appspot.gserviceaccount.com>

coreboot/vboot,coreboot/vboot,coreboot/vboot,coreboot/vboot,coreboot/vboot