[WIP] Locality Sensitive Hashing for approximate nearest neighbor search(GSoC)

please define a local variable:

```python
rng_seed = random_state.randint(0, 10)
```

to avoid this ugly indentation.

BTW where does the hardcoded "10" comes from? That sounds like an unwanted bias to me. You can use `np.iinfo(np.int32).max` instead, I think.