Fix translucent multifrustum artifact

Does not overlap frustums when drawing translucent geometry. I haven't noticed any tearing and it seems the translucent overdraw is more noticeable and happens more often.

Before:
![image](https://f.cloud.github.com/assets/1494815/2144138/0108f404-9380-11e3-95a1-987bdb2fcf4c.png)
After:
![image](https://f.cloud.github.com/assets/1494815/2144160/91c54664-9380-11e3-8d59-c42373c8ce7e.png)