Fix signature mismatch

svn path=/nixpkgs/trunk/; revision=17313

pkgs/top-level/guile-2-test.nix

@@ -6,8 +6,9 @@
 let
   allPackages = import ./all-packages.nix;
 
-  pkgs = let orig = (allPackages {}); in
+  pkgsFun = {system ? builtins.currentSystem}: let orig = (allPackages {inherit system;}); in
     orig // { __overrides = { guile = orig.guile_1_9; }; };
+  pkgs = pkgsFun {};
 
   toJob = x: if builtins.isAttrs x then x else
     { type = "job"; systems = x; schedulingPriority = 10; };
@@ -18,7 +19,7 @@ let
      for the platform in question. */
   testOn = systems: f: {system ? builtins.currentSystem}:
     if pkgs.lib.elem system systems
-    then f (pkgs {inherit system;})
+    then f (pkgsFun {inherit system;})
     else {};
 
   /* Map an attribute of the form `foo = [platforms...]'  to `testOn