* Revert r18985, but now handle the case where a nixbld user doesn't   exist yet.  Ludo's original patch only worked in the "update" case.   Also, do this only for the nixbld group.
* Revert r18985, but now handle the case where a nixbld user doesn't
  exist yet.  Ludo's original patch only worked in the "update" case.
  Also, do this only for the nixbld group.


git-svn-id: 71c8032c709790ec749031c4215f8515ac00dc5a@18990 70bd8c7a-acb8-0310-9f0d-9cc1c95dcdbb

bnordgren/nixos,bnordgren/nixos,bnordgren/nixos,bnordgren/nixos,bnordgren/nixos