Fix grub package names again
    
    When building the install trees, lorax doesn't follow Provides,
    so even though grub2-pc, grub2-ppc64 etc. Provide grub2 and
    grub2-efi-x64, grub2-efi-ia32 etc. Provide grub2-efi, they
    don't get installed, and that stops installs from working.
    Although it's messy, we'll just have to list all the archful
    package names like this.