Segmentation fault: 11 with encoded HTML characters
#### Code Sample, a copy-pastable example if possible

```python
#!/usr/bin/python

import MySQLdb
import pandas as pd
import pprint as pp
import os
import sys
import HTMLParser
parser = HTMLParser.HTMLParser()

def get_script_path():
	return os.path.dirname(os.path.realpath(sys.argv[0]))
script_path = get_script_path() 

db = MySQLdb.connect("","","","" )

df = pd.read_sql("SELECT * from test limit 1000",db)

df.to_json(script_path+'/query_resutls.json')
```
#### Problem description

I got a plain 'Segmentation fault: 11' when running this code on the Terminal.app 
I believe the problem was that one of the columns had currency names encoded in HTML. The USD are encoded as "D&oacute;lares" from the spanish "Dólares".

pandas (0.20.3)
Python 2.7.13
MacOS High Sierra 10.13.2

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

<details>
[paste the output of ``pd.show_versions()`` here below this line]

INSTALLED VERSIONS
------------------
commit: None
python: 2.7.13.final.0
python-bits: 64
OS: Darwin
OS-release: 17.3.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.20.3
pytest: None
pip: 9.0.1
setuptools: 36.6.0
Cython: None
numpy: 1.13.3
scipy: None
xarray: None
IPython: 5.4.1
sphinx: None
patsy: None
dateutil: 2.6.1
pytz: 2017.2
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: None
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: 4.6.0
html5lib: 0.9999999
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.9.6
s3fs: None
pandas_gbq: None
pandas_datareader: None
</details>
