Attach a bunch of meta.branch info for the monitor

This should stop explicitly-versioned expressions from showing up in the
monitor as in need of update.

pkgs/development/libraries/db/generic.nix

@@ -6,6 +6,7 @@
 , version, sha256
 , extraPatches ? [ ]
 , license ? stdenv.lib.licenses.sleepycat
+, branch ? null
 }:
 
 stdenv.mkDerivation rec {
@@ -37,5 +38,6 @@ stdenv.mkDerivation rec {
     description = "Berkeley DB";
     license = license;
     platforms = platforms.unix;
+    branch = branch;
   };
 }