[Nix-dev] Nixos tests massive regression

[Luca Bruno]

See http://hydra.nixos.org/jobset/nixos/trunk-combined#tabs-jobs

I tried building openssh test locally and I get:
10.559484] sshd[1593]:
/nix/store/i7lip0m84naddaf9dn5kh03h1dzr90wk-openssh-6.6p1/empty must be
owned by root and not group or world-writable.

I tried bisecting down to the latest successful evaluation but I
couldn't find the bad commit.