bzip2: update patch URL

For some reason ftp.suse.com refuses connections via IPv6 on HTTPS,
which breaks download from IPv6-only network. This commit changes
protocol to FTP, which works fine via IPv6 and which is consistent with
other mention of this domain in nixpkgs.

pkgs/tools/compression/bzip2/default.nix

@@ -25,7 +25,7 @@ in {
 
   patches = [
     (fetchurl {
-      url = "https://ftp.suse.com/pub/people/sbrabec/bzip2/for_downstream/bzip2-1.0.6.2-autoconfiscated.patch";
+      url = "ftp://ftp.suse.com/pub/people/sbrabec/bzip2/for_downstream/bzip2-1.0.6.2-autoconfiscated.patch";
       sha256 = "sha256-QMufl6ffJVVVVZespvkCbFpB6++R1lnq1687jEsUjr0=";
     })
   ];