add branch info

pkgs/applications/audio/ardour/default.nix

@@ -43,6 +43,7 @@ stdenv.mkDerivation rec {
       Also read "The importance of Paying Something" on their homepage, please!
     '';
     homepage = http://ardour.org/;
+    branch  = "2";
     license = "GPLv2";
     maintainers = [ stdenv.lib.maintainers.marcweber ];
     platforms = stdenv.lib.platforms.linux;

pkgs/development/tools/misc/autoconf/2.13.nix

@@ -19,6 +19,7 @@ stdenv.mkDerivation rec {
   meta = {
     homepage = http://www.gnu.org/software/autoconf/;
     description = "Part of the GNU Build System";
+    branch = "2.13";
 
     longDescription = ''
       GNU Autoconf is an extensible package of M4 macros that produce

pkgs/servers/http/apache-httpd/2.2.nix

@@ -55,6 +55,7 @@ stdenv.mkDerivation rec {
 
   meta = {
     description = "Apache HTTPD, the world's most popular web server";
+    branch      = "2.2";
     homepage    = http://httpd.apache.org/;
     license     = stdenv.lib.licenses.asl20;
     platforms   = stdenv.lib.platforms.linux ++ stdenv.lib.platforms.darwin;