Game crash when switching texturepack (resource pack)

Put the summary of the bug you're having here

*What I expected to happen was...:*The game crashed when i switched from a custom resource pack to a default one. In my custom pack some textures was not showing properly. Lamps for ex had an purple and white texture and when i switched back to default the game crashes.

Describe what you thought should happen here

What actually happened was...:
Game error when switching between old resourcepack to default.
Describe what happened here

Steps to Reproduce:
1. Use a custom resourcepack which i made when 13w24a whas released
2. Upgraded launcher and game. Switched to custom resourcepack
3. Play the game and switch to default resourcepack