If nixos-install is run on a machine with `nix.distributedBuilds = true`
the installation will fail at some point like this:
Died at /nix/store/4frhrl31cl7iahlz6vyvysy5dmr6xnh3-nix-1.10/libexec/nix/build-remote.pl line 115, <STDIN> line 1.
This is due to `nix.distributedBuilds` setting
NIX_BUILD_HOOK=/nix/store/.../build-remote.pl in the global environment,
which then gets confused in the minimal chroot created by nixos-install.
To avoid these kinds of issues with build hooks, just disable them in
the chroot.