Bug#963962: Update: /etc/grub.d/20_linux_xen

[Sergio Gelato]

Some minor additions:

1. It turns out #924360 is no longer a concern. Not that I can see, anyway.
2. This is what I get when trying to boot from the .efi entry:

----<snip>------
Loading Xen 4.11-amd64.efi ...Loading Xen 4.11-amd64.efi ...

error: invalid arch-dependent ELF magic.
error: invalid arch-dependent ELF magic.
Loading Linux 4.19.0-9-amd64 ...Loading Linux 4.19.0-9-amd64 ...

error: you need to load the kernel first.
error: you need to load the kernel first.
Loading initial ramdisk ...Loading initial ramdisk ...

error: you need to load the kernel first.
error: you need to load the kernel first.


Press any key to continue...Press any key to continue...
----<snip>------

So at this time I don't see a point in generating those .efi menu entries.