nixos-iso: Re-enable new kernel iso images (close #2839)

nixos/modules/installer/cd-dvd/installation-cd-graphical-new-kernel.nix

···
+{ config, pkgs, ... }:
+
+{
+  imports = [ ./installation-cd-graphical.nix ];
+
+  boot.kernelPackages = pkgs.linuxPackages_latest;
+}

nixos/modules/installer/cd-dvd/installation-cd-minimal-new-kernel.nix

···
 {
   imports = [ ./installation-cd-minimal.nix ];
 
-  boot.kernelPackages = pkgs.linuxPackages_3_10;
-  boot.vesa = false;
+  boot.kernelPackages = pkgs.linuxPackages_latest;
 }

nixos/modules/installer/cd-dvd/installation-cd-new-kernel.nix

···
-{ config, pkgs, ... }:
-
-{
-  imports = [ ./installation-cd-graphical.nix ];
-
-  boot.kernelPackages = pkgs.linuxPackages_3_10;
-  boot.vesa = false;
-}

nixos/release.nix

···
     inherit system;
   });
 
-  /*
-  iso_minimal_new_kernel = forAllSystems (system: makeIso {
-    module = ./modules/installer/cd-dvd/installation-cd-minimal-new-kernel.nix;
-    type = "minimal-new-kernel";
-    inherit system;
-  });
-  */
-
   iso_graphical = forAllSystems (system: makeIso {
     module = ./modules/installer/cd-dvd/installation-cd-graphical.nix;
     type = "graphical";
···
 
   # A variant with a more recent (but possibly less stable) kernel
   # that might support more hardware.
-  /*
-  iso_new_kernel = forAllSystems (system: makeIso {
-    module = ./modules/installer/cd-dvd/installation-cd-new-kernel.nix;
-    type = "new-kernel";
+  iso_minimal_new_kernel = forAllSystems (system: makeIso {
+    module = ./modules/installer/cd-dvd/installation-cd-minimal-new-kernel.nix;
+    type = "minimal-new-kernel";
+    inherit system;
+  });
+
+  iso_graphical_new_kernel = forAllSystems (system: makeIso {
+    module = ./modules/installer/cd-dvd/installation-cd-graphical-new-kernel.nix;
+    type = "graphical-new-kernel";
     inherit system;
   });
-  */
 
 
   # A bootable VirtualBox virtual appliance as an OVA file (i.e. packaged OVF).