Fix license on unRAR to unfree.

This license is BAD and it needs to be caught. You need to agree to the
use conditions or you have to remove the software from your machine
which makes it not redistributable.

cc @ehmry

pkgs/tools/archivers/unrar/default.nix

@@ -25,7 +25,7 @@ stdenv.mkDerivation {
 
   meta = {
     description = "Utility for RAR archives";
-    license = "freeware";
+    license = stdenv.lib.licenses.unfree;
     maintainers = [ stdenv.lib.maintainers.emery ];
     platforms = stdenv.lib.platforms.linux ++ stdenv.lib.platforms.darwin; # arbitrary
   };