Don't use "with licenses;" for single licences

And don't use square brackets on such lines.

pkgs/development/libraries/libcli/default.nix

@@ -18,7 +18,7 @@ stdenv.mkDerivation rec {
   meta = with stdenv.lib; {
     description = "Emulate a Cisco-style telnet command-line interface";
     homepage = http://sites.dparrish.com/libcli;
-    license = with licenses; lgpl21Plus;
+    license = licenses.lgpl21Plus;
     platforms = with platforms; linux;
     maintainers = with maintainers; [ nckx ];
   };