GRUB_OPTS has never been documented as externally available, and is
not used. Assume it's value to simplify the code.
Move the grub version check separately, as we only support grub2
Remove references to buliding i386 images. I don't image it works in
any way.
Remove ci.md, which is no longer relevant.
Refactor the test for "building BIOS image on EFI system" consiberably
after these changes.
Change-Id: Ia99687815667c3cf5e82cf21d841d3b1008b8fa9
