Include the URL of the binary cache in .nixpkg files

Dependencies

• [2] ON4DDIBZ * Forgot to commit.
• [3] UXVDOUBJ

Change contents

• replacement in src/lib/Hydra/View/NixPkg.pm at line 15
  [2.327]→[2.327:384](∅→∅)
  − . " " . $build->drvpath . " " . $build->outpath;
  [2.327]

  [2.384]
  + . " " . $build->drvpath . " " . $build->outpath

  + . " " . $c->uri_for('/');