Including the bash-completion package in bash itself sounded like a good idea
at the time, but it wasn't. After having actually integrated completion support
into NixOS, it has become obvious that this property isn't required at all.
Keeping bash-completion separate from bash works just fine. Anyone who wants
completion support can just install that package.
svn path=/nixpkgs/trunk/; revision=29467
3e09798bf4