Warning on `import distributed`

```
/Library/Python/2.7/site-packages/dask-0.7.6-py2.7.egg/dask/array/numpy_compat.py:29: RuntimeWarning: divide by zero encountered in divide
  or not np.allclose(np.divide(1, .5, dtype='i8'), 2)
```

Can give more details on system if needed.
