[SOLVED - NOT BUG] DataFrame.rename method changing the datetime format.
The Rename Method from DataFrame convert de datetime format in the original form.
I have a datetime in the format %Y-%m-%d in a DataFrame. Before I use de rename method this DataFrame change the format to %Y-%m-%d 00:00:00. This is a Bug? isn't correct rename the index too. I think that this method should only rename de columns that i put

A Example:

![image](https://user-images.githubusercontent.com/25715921/52919335-3b45bd00-32e0-11e9-8417-f5adbabb4919.png)
