Bjørn Forsman aff4394be6 nixos-generate-config: fix nix-env example command
An escape char is needed to prevent "$ nix" from being evaluated and
expanded to an empty string. With this change the resulting text is

  $ nix-env -qaP | grep wget

instead of

  -env -qaP | grep wget
2014-06-12 21:18:21 +02:00
..
2014-03-07 19:39:55 +01:00