Fix Persona logins

Dependencies

• [2] TTZ26BJQ Unify Hydra's NixOS module with the one used for hydra.nixos.org
• [*] D3MDJONY

Change contents

• edit in hydra-module.nix at line 22
  [2.142]

  [2.142]
  + OPENSSL_X509_CERT_FILE = "/etc/ssl/certs/ca-certificates.crt"; # FIXME: remove on NixOS >= 15.07