core/tests: Remove beegfs test

The test has been removed upstream[1] for the following reason[2]:

> BeeGFS is a fantastic high performance file system. However, after
> running it for a few months last year the meta data daemon kept
> crashing randomly in production use (support from the manufacturer
> requires a paid support contract). The current version that is nixpkgs
> is outdated and I do not want to maintain it any longer. The build
> system is purely based on make file and is hard to maintain.

[1]: NixOS/nixpkgs@c3e17ef
[2]: NixOS/nixpkgs#66352

Signed-off-by: aszlig <aszlig@nix.build>

modules/core/tests.nix

@@ -20,9 +20,6 @@ let
     { check = config.services.avahi.enable;
       path  = ["nixos" "avahi"];
     }
-    { check = config.services.beegfsEnable;
-      path  = ["nixos" "beegfs"];
-    }
     { check = config.vuizvui.createISO;
       paths = [
         ["nixos" "boot" "biosCdrom"]