Nixpkgs: `nix-env -u` replaces nixos.audacious with nixos.audaciousQt5

[ben0x539]

I guess it's a political question whether Qt is an upgrade from Gtk, but for whatever reason the Qt version appears to have text in the toolbar instead of icons, so I'd like to stick with the inferior Gtk for now.

Issue description

nixos.audacious{,Qt5} have the same name, but versions 3.8 and 3.8.1 respectively.

Steps to reproduce

$ nix-env -iA nixos.audacious
$ nix-env -u audacious

Technical details

$ nixos-version
17.03pre100522.01fef3f (Gorilla)
$ nix-env --version
nix-env (Nix) 1.11.6
$ nix-instantiate --eval '<nixpkgs>' -A lib.nixpkgsVersion
"17.03pre100522.01fef3f"

[FRidh]

What I understand from their website they support both. If we want to support both they should have different names.