Applying OG vocab for hiding vocabularies without any terms.

#5878 
Before:
![before patch](https://cloud.githubusercontent.com/assets/1222368/2730062/52c59e58-c613-11e3-9322-cb6af2d708dd.png)
After:
![after patch](https://cloud.githubusercontent.com/assets/1222368/2730061/52911a34-c613-11e3-9595-2a281fa4d6ec.png)