Need of `fetchurl.nix`

[Anton-Latukha]

After the update of submodule #1029, Nix relocated the place of fetchurl.nix & now:

cabal v2-run hnix -- -I /nix/var/nix/profiles/per-user/root/channels --eval --expr '(import <old> {}).qbittorrent.outPath'
...
file ''nix/fetchurl.nix'' was not found in the Nix search path (add it's using $NIX_PATH or -I)

Supplying the fetchurl.nix directly works:

cabal v2-run hnix -- -I /nix/var/nix/profiles/per-user/root/channels -I $(pwd)/nix/fetchurl.nix --eval --expr '(import <old> {}).qbittorrent.outPath'
Up to date
"/nix/store/xqgcn5mgjwzpwv848725wqr2acm8qc8w-qbittorrent-4.3.1"

[soulomoon]

After #1051
We no longer need fetchurl.nix