Sparse becomes float under fancy indexing
``` python
>>> pd.SparseSeries([False, True], dtype=bool)[[0, 1]]
0    0.0
1    1.0
dtype: float64
BlockIndex
Block locations: array([1], dtype=int32)
Block lengths: array([1], dtype=int32)
```
#### Expected output

```
0    False
1    True
dtype: bool
BlockIndex
Block locations: array([1], dtype=int32)
Block lengths: array([1], dtype=int32)
```
#### Output of `pd.versions()`

pandas: 0.18.1

should alone be relevant.

Apologies I've not checked if this is fixed by #13849 or elsewhere. Just passing on issues from 
https://github.com/scikit-learn/scikit-learn/issues/7352.
