0.17 changes behavior of division of DataFrame by Series in presence of DateTimeIndex
Older versions up to 0.16.2:

``` python
import pandas as pd
print(pd.__version__)
index = pd.date_range(start='2000-1-1', end='2000-1-3')
pd.DataFrame({1: [3, 3, 3], 2: [6, 6, 6]}, index=index) / pd.Series([2, 2, 2], index=index)
```

```
0.14.0rc1-33-g8c1f550
1   2
2000-01-01  1.5 3
2000-01-02  1.5 3
2000-01-03  1.5 3
```

0.17:

```
0.17.0
2000-01-01 00:00:00 2000-01-02 00:00:00 2000-01-03 00:00:00 1   2
2000-01-01  NaN NaN NaN NaN NaN
2000-01-02  NaN NaN NaN NaN NaN
2000-01-03  NaN NaN NaN NaN NaN
```

Work-around:
Use `df.divide(series, axis='index')`. 

Is this change in API intentional? Couldn't find it in the release announcements.
