Pandas 0.15.1 df.interpolate().plot() wrong result with NaT in datelike index
I am using a DataFrame df with dates as index and some data with missing values.
All dates are from the same year 1999 and the data has some missing vales.
There is one record in the dates that is NaT.

When I use df.interploate().plot() a line is plotted between 1996 and 1716. 
When NaT is committed the correct plot appears. 
