copy-tarballs: Use an S3 bucket for tarballs.nixos.org

Tarballs.nixos.org is now stored in an S3 bucket rather than an EBS
volume. Redirects are used to simulate symlinks.

The function find-tarballs.nix now filters out fetchzip, fetchpatch
and the like.

maintainers/scripts/find-tarballs.nix

@@ -4,9 +4,11 @@
 with import ../.. { };
 with lib;
 
+{ expr ? removeAttrs (import ../../pkgs/top-level/release.nix { }) [ "tarball" "unstable" ] }:
+
 let
 
-  root = removeAttrs (import ../../pkgs/top-level/release.nix { }) [ "tarball" "unstable" ];
+  root = expr;
 
   uniqueUrls = map (x: x.file) (genericClosure {
     startSet = map (file: { key = file.url; inherit file; }) urls;
@@ -15,7 +17,10 @@ let
 
   urls = map (drv: { url = head drv.urls; hash = drv.outputHash; type = drv.outputHashAlgo; }) fetchurlDependencies;
 
-  fetchurlDependencies = filter (drv: drv.outputHash or "" != "" && drv ? urls) dependencies;
+  fetchurlDependencies =
+    filter
+      (drv: drv.outputHash or "" != "" && drv.outputHashMode == "flat" && drv.postFetch or "" == "" && drv ? urls)
+      dependencies;
 
   dependencies = map (x: x.value) (genericClosure {
     startSet = map keyDrv (derivationsIn' root);