## What changes were proposed in this pull request?

This should be credited to mvervuurt. The main purpose of this PR is
 - simply to include the change for the same instance in `DataFrameReader` just to match up.
 - just avoid duplicately verifying the PR (as I already did).

The documentation for both should be the same because both assume the `properties` should be  the same `dict` for the same option.

## How was this patch tested?

Manually building Python documentation.

This will produce the output as below:

- `DataFrameReader`

![2016-08-17 11 12 00](https://cloud.githubusercontent.com/assets/6477701/17722764/b3f6568e-646f-11e6-8b75-4fb672f3f366.png)

- `DataFrameWriter`

![2016-08-17 11 12 10](https://cloud.githubusercontent.com/assets/6477701/17722765/b58cb308-646f-11e6-841a-32f19800d139.png)

Closes #14624

Author: hyukjinkwon <gurwls223@gmail.com>
Author: mvervuurt <m.a.vervuurt@gmail.com>

Closes #14677 from HyukjinKwon/typo-python.