bug#26339: [PATCH 01/18] system: Pass <bootloader-parameter> to grub.

[Danny Milosavljevic <dannym@scratchpost.org>]

> diff --git a/gnu/system/grub.scm b/gnu/system/grub.scm
> index 4f9bde6a6..f2838d633 100644
> --- a/gnu/system/grub.scm
> +++ b/gnu/system/grub.scm
> @@ -298,9 +309,9 @@ corresponding to old generations of the system."
>                    #$initrd)))))
>  
>    (mlet %store-monad ((sugar (eye-candy config
> -                                        (menu-entry-device (first entries))
> +                                        (menu-entry-device (first all-entries))
>                                          (menu-entry-device-mount-point
> -                                         (first entries))
> +                                         (first all-entries))
>                                          #:system system
>                                          #:port #~port)))
>      (define builder

... oops.  (first entries) could indeed fail if the list of profile generations is empty.  That shouldn't happen but anyway, the new way is safer.

Applied only this chunk to master as 0ab1e8ae8892c92fd7a1fd07430ba6f2b710668d.