Add meta.branch to a bunch of packages

Gives better results in the monitor

pkgs/development/libraries/libsigsegv/2.5.nix

@@ -2,7 +2,7 @@
 
 stdenv.mkDerivation rec {
   name = "libsigsegv-2.5";
-  
+
   src = fetchurl {
     url = "mirror://gnu/libsigsegv/${name}.tar.gz";
     sha256 = "0fvcsq9msi63vrbpvks6mqkrnls5cfy6bzww063sqhk2h49vsyyg";
@@ -11,6 +11,7 @@ stdenv.mkDerivation rec {
   meta = {
     homepage = http://libsigsegv.sf.net;
     description = "A library for handling page faults in user mode";
+    branch = "2.5";
   };
 
   doCheck = true;