Revert "protobuf: Clean up and update to version 2.6.1."

This reverts commit 18b306b041. Protobuf
releases are generally not very backwards compatible and likely to
break lots of stuff. E.g.

  http://hydra.nixos.org/build/17535340
  http://hydra.nixos.org/build/17535640
  http://hydra.nixos.org/build/17536998
  http://hydra.nixos.org/build/17536170

See also b851e970da.

pkgs/development/libraries/protobuf/default.nix

@@ -1,41 +1,28 @@
-{ stdenv, fetchFromGitHub, autoconf, automake, libtool, zlib, gtest }:
+{ fetchurl, stdenv, zlib }:
 
 stdenv.mkDerivation rec {
-  name = "protobuf-${version}";
-  version = "2.6.1";
+  name = "protobuf-2.5.0";
 
-  src = fetchFromGitHub {
-    owner = "google";
-    repo = "protobuf";
-    rev = version;
-    sha256 = "03df8zvx2sry3jz2x4pi3l32qyfqa7w8kj8jdbz30nzy0h7aa070";
+  src = fetchurl {
+    url = "http://protobuf.googlecode.com/files/${name}.tar.bz2";
+    sha256 = "0xxn9gxhvsgzz2sgmihzf6pf75clr05mqj6218camwrwajpcbgqk";
   };
 
-  postPatch = ''
-    sed -i -e '/gtest/d' Makefile.am
-    sed -i \
-      -e 's!\$(top_\(build\|src\)dir)/gtest!${gtest}!g' \
-      -e 's/\(libgtest[^.]*\.\)la/\1a/g' \
-      src/Makefile.am
-  '';
-
-  buildInputs = [ zlib autoconf automake libtool gtest ];
-
-  preConfigure = "autoreconf -vfi";
+  buildInputs = [ zlib ];
 
   doCheck = true;
 
   meta = {
     description = "Protocol Buffers - Google's data interchange format";
 
-    longDescription = ''
-      Protocol Buffers are a way of encoding structured data in an
-      efficient yet extensible format. Google uses Protocol Buffers for
-      almost all of its internal RPC protocols and file formats.
-    '';
+    longDescription =
+      '' Protocol Buffers are a way of encoding structured data in an
+         efficient yet extensible format.  Google uses Protocol Buffers for
+         almost all of its internal RPC protocols and file formats.
+      '';
 
-    license = stdenv.lib.licenses.bsd3;
+    license = "mBSD";
 
-    homepage = "https://developers.google.com/protocol-buffers/";
+    homepage = http://code.google.com/p/protobuf/;
   };
 }