[core-updates] Due to flawed bootstrap tarball, full rebuild needed

[Mark H Weaver]

Hello Guix,

It turns out that the MesCC bootstrap tarball includes store references,
and moreover it references a different store item than the MesCC
bootstrap tarball that I built locally on my own machine.  See
<https://issues.guix.gnu.org/issue/36747> for details and a proposed
patch from Janneke to fix the problem.

In my opinion, we should update the bootstrap binaries and rebuild
'core-updates' from scratch.  What do other people think?

       Mark