nixos/netboot: Fix evaluation error

The function arguments for make-squashfs.nix have changed in
df117acab7bf345500ffada26c240c9f815b7c21, so we need to change them here
as well.

The boot.netboot NixOS VM test now succeeds again.

Signed-off-by: aszlig <[e-mail]>
Cc: @edolstra

nixos/modules/installer/netboot/netboot.nix

···
 
     # Create the squashfs image that contains the Nix store.
     system.build.squashfsStore = import ../../../lib/make-squashfs.nix {
-      inherit (pkgs) stdenv squashfsTools perl pathsFromGraph;
+      inherit (pkgs) stdenv squashfsTools closureInfo;
       storeContents = config.netboot.storeContents;
     };