bug#32652: ‘guix system vm -d’ output is non-deterministic

[Ludovic Courtès]

Hello,

On IRC georges-duperon reported that the output of “guix system vm -d
config.scm” is non-deterministic, which is indeed the case as of
fd3a64335da5a591dbe9276395d0ad6bb09f00bb.

We determined that the difference is in the
“builder-in-linux-vm-builder” items, specifically the root partition
UUID as computed by ‘operating-system-uuid’, and even more precisely,
this bit:

              (hash (operating-system-services os)
                    (- (expt 2 32) 1))

Ludo’.