gnutls: fix tests after 79bd4ad57 (PR #61179)
gnutls: fix tests after 79bd4ad57 (PR #61179)

It's one of the places that would reach out to /etc/ otherwise,
so I expect we have to pay this price to get the effect.
Hopefully there won't be too many places to patch.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs