subdl: fix attribute ordering, fix version

pkgs/applications/video/subdl/default.nix

···
 
 stdenv.mkDerivation {
   pname = "subdl";
-  version = "0.0pre.2017.11.06";
+  version = "unstable-2017-11.06";
 
   src = fetchFromGitHub {
     owner = "alexanderwink";
···
     sha256 = "0kmk5ck1j49q4ww0lvas2767kwnzhkq0vdwkmjypdx5zkxz73fn8";
   };
 
+  buildInputs = [ python3 ];
+
+  installPhase = ''
+    install -vD subdl $out/bin/subdl
+  '';
+
   meta = {
     homepage = "https://github.com/alexanderwink/subdl";
     description = "A command-line tool to download subtitles from opensubtitles.org";
···
     license = lib.licenses.gpl3;
     maintainers = [ lib.maintainers.exfalso ];
   };
-
-  buildInputs = [ python3 ];
-
-  installPhase = ''
-    install -vD subdl $out/bin/subdl
-  '';
 }