* hydra/release.nix: remove supportOldDBs

Dependencies

• [2] HPIJ35SG
• [3] T4LLYESZ * Nix expression for building Hydra.
• [4] SAFVRDTK * Put Hydra's dependencies so that they can easily be installed in a

Change contents

• replacement in release.nix at line 63
  [2.185]→[2.185:253](∅→∅)
  − let nix = nixUnstable.override { supportOldDBs = false; }; in
  [2.185]

  [3.925]
  + let nix = nixUnstable; in