fix evaluation (bad meta.license)

pkgs/development/libraries/qtkeychain/default.nix

···
   meta = {
     description = "Platform-independent Qt API for storing passwords securely";
     homepage = "https://github.com/frankosterfeld/qtkeychain";
-    license = stdenv.lib.licenses.BSD3;
+    license = stdenv.lib.licenses.bsd3;
   };
 }

pkgs/development/libraries/websocket++/default.nix

···
   meta = {
     homepage = "http://www.zaphoyd.com/websocketpp/";
     description = "C++/Boost Asio based websocket client/server library";
-    license = stdenv.lib.licenses.BSD3;
+    license = stdenv.lib.licenses.bsd3;
   };
 }