lol

nixos/tests: Make pure

Just had @fabianhauser at the #ZurichZHF hackathon run into this, causing the
tests to fail evaluation due to some system impurity

+1 -1
+1 -1
nixos/tests/make-test-python.nix
··· 1 1 f: { 2 2 system ? builtins.currentSystem, 3 - pkgs ? import ../.. { inherit system; }, 3 + pkgs ? import ../.. { inherit system; config = {}; overlays = []; }, 4 4 ... 5 5 } @ args: 6 6