dataframe plot method throws an error
#### Code Sample, a copy-pastable example if possible

```python
import pandas as pd
import numpy as np
import matplotlib
import matplotlib.pyplot as plt

ts = pd.Series(np.random.randn(1000), index=pd.date_range('1/1/2000', periods=1000))
ts = ts.cumsum()
ts.plot()

```
#### Problem description

Getting an error: 

NameError: name '_converter' is not defined

https://stackoverflow.com/questions/48341233/ts-plot-and-dataframe-plot-throwing-error-nameerror-name-converter-is

#### Expected Output
chart as usual

#### Output of ``pd.show_versions()``

<details>

INSTALLED VERSIONS
------------------
commit: None
python: 3.6.2.final.0
python-bits: 64
OS: Linux
OS-release: 4.9.75-25.55.amzn1.x86_64
machine: x86_64
processor: 
byteorder: little
LC_ALL: C.UTF-8
LANG: C.UTF-8
LOCALE: en_US.UTF-8

pandas: 0.22.0
pytest: 3.3.2
pip: 9.0.1
setuptools: 36.5.0.post20170921
Cython: 0.27.3
numpy: 1.13.3
scipy: None
pyarrow: None
xarray: None
IPython: 6.2.1
sphinx: None
patsy: None
dateutil: 2.6.1
pytz: 2017.3
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: 2.1.2
openpyxl: 2.4.9
xlrd: None
xlwt: None
xlsxwriter: None
lxml: 4.1.1
bs4: 4.6.0
html5lib: 1.0.1
sqlalchemy: 1.2.1
pymysql: 0.8.0
psycopg2: None
jinja2: 2.10
s3fs: None
fastparquet: 0.1.3
pandas_gbq: None
pandas_datareader: None

</details>
