This seems to have combined badly with the systemd upgrade, we'll revert for now and revisit after the 14.04 branch. This reverts commitad80532881, reversing changes made to1c5d3c7883.
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at http://nixos.org/nixos and in the manual in doc/manual.