Have an empty resourcepack correctly formated for 1.8.

Open minecraft snapshot 15w33c, go to resource packs list.

See your resource pack in red tagged as Incompatible.

Go to said resource pack, open its pack.mcmeta file and change "pack_format" value from 1 to 2, save the changes.

Go to minecraft, close and reopen the resource pack list. You'll still see it in red, tagged as Incompatible and receiving the "Are you sure you want to load this resource pack?" screen.

I don't think this is intended since we can change resource pack names, even add or delete resource packs, and see it all reflected on the minecraft menu without restarting the game.