move import os just below the func def

the 'import os' was missing for os.getenv('USER'). Was giving me an error.

![bug](https://f.cloud.github.com/assets/227817/2073657/3a3d49ea-8d64-11e3-87ee-31a12b1d6f3a.png)

Hence moved 'import os' up below func def.