nixos/release-combined: Add boot-stage1 test

We don't want to push out a channel update whenever this test fails,
because that might have unexpected and confused side effects and it
*really* means that stage 1 of our boot up is broken.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

nixos/release-combined.nix

@@ -67,6 +67,7 @@ in rec {
         (all nixos.tests.boot.biosUsb)
         (all nixos.tests.boot.uefiCdrom)
         (all nixos.tests.boot.uefiUsb)
+        (all nixos.tests.boot-stage1)
         (all nixos.tests.ipv6)
         (all nixos.tests.kde4)
         #(all nixos.tests.lightdm)