local-grid: Remove some configuration that matches the defaults.

morph/lib/hardware-virtual.nix

@@ -8,16 +8,10 @@
 
   virtualisation.virtualbox.guest.enable = true;
 
-  # Use the GRUB 2 boot loader.
-  boot.loader.grub.enable = true;
-  boot.loader.grub.version = 2;
   boot.loader.grub.device = "/dev/sda";
 
   boot.initrd.availableKernelModules = [ "ata_piix" "sd_mod" "sr_mod" ];
-  boot.initrd.kernelModules = [ ];
   boot.kernel.sysctl = { "vm.swappiness" = 0; };
-  boot.kernelModules = [ ];
-  boot.extraModulePackages = [ ];
 
   # remove the fsck that runs at startup. It will always fail to run, stopping
   # your boot until you press *.
@@ -33,7 +27,6 @@
     { device = "/dev/sda1";
       fsType = "ext4";
     };
-  swapDevices = [ ];
 
   # We want to push packages with morph without having to sign them
   nix.trustedUsers = [ "@wheel" "root" "vagrant" ];