change to closed module so OBS works NVIDIA/open-gpu-kernel-modules#689

configuration.nix

@@ -75,7 +75,7 @@
       modesetting.enable = true;
       package = config.boot.kernelPackages.nvidiaPackages.latest;
       # Use open-source kernel module?
-      open = true;
+      open = false;
     };
   };