Merge ~ubuntu-core-dev/grub/+git/ubuntu:sil2100/use-auto-nvram into ~ubuntu-core-dev/grub/+git/ubuntu:ubuntu

This doesn't look correct to me. The debian/postinst.in is used to generate the postinst of (among others) grub-efi-amd64 and grub-pc. In the EFI+BIOS coinstallability case, I would expect to see grub-pc installed, but not grub-efi-amd64: we would only install shim-signed + grub-efi-amd64-bin (+signed). Therefore, the one version of the script that actually *cares* about --auto-nvram is the one we would normally not expect to have installed.

Also see the $NO_NVRAM variable elsewhere in the code, which is specifically set only for EFI packages and passed as an argument to run_grub_install. If any changes should be made to this script to support --auto-nvram (which I think is unnecessary), they should be made there.

Agreed, maybe I rushed with this MP a bit. It doesn't seem to be needed here. Let's drop it.

As for $NO_NVRAM, I agree it might be slightly cleaner to do it that way - but since --auto-nvram respects --no-nvram, I decided to introduce a one-line-diff instead of a multi-line one having to modify $NO_NVRAM (or introducing something like $AUTO_NVRAM). It seemed like useless copy-pasting of code. When --no-nvram is given along with --auto-nvram, no magic is done and simply no NVRAM operations are being done.