TypeError: object of type 'NoneType' has no len() with MySQL empty columns
pandas '0.11.0'
mysql.connector '1.0.9'
# Import statements and options

import mysql.connector
from mysql.connector import errorcode
import pandas.io.sql as sql
import pandas as pd
from pandas import DataFrame
## Error

Running this code against MySQL (view includes several completely blank columns):

``` python
#Queries for CCI since Nov 2012
queries = sql.read_frame("select * from vw_queries_lj where query_account_id='34' and from_unixtime(query_created, '%Y-%m-%d') >= '2012-11-01' limit 100;", con)
```

Causes this error:

``` python
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-17-78e88f1ac26a> in <module>()
      1 #Queries for CCI since Nov 2012
----> 2 queries = sql.read_frame("select * from vw_queries_lj where query_account_id='34' and from_unixtime(query_created, '%Y-%m-%d') >= '2012-11-01' limit 100;", con)
      3 

/Users/randyzwitch/anaconda/lib/python2.7/site-packages/pandas/io/sql.pyc in read_frame(sql, con, index_col, coerce_float, params)
    160 
    161     result = DataFrame.from_records(rows, columns=columns,
--> 162                                     coerce_float=coerce_float)
    163 
    164     if index_col is not None:

/Users/randyzwitch/anaconda/lib/python2.7/site-packages/pandas/core/frame.pyc in from_records(cls, data, index, exclude, columns, coerce_float, nrows)
   1070         else:
   1071             arrays, arr_columns = _to_arrays(data, columns,
-> 1072                                              coerce_float=coerce_float)
   1073 
   1074             arr_columns = _ensure_index(arr_columns)

/Users/randyzwitch/anaconda/lib/python2.7/site-packages/pandas/core/frame.pyc in _to_arrays(data, columns, coerce_float, dtype)
   5449         return arrays, columns
   5450 
-> 5451     if len(data) == 0:
   5452         return [], []  # columns if columns is not None else []
   5453     if isinstance(data[0], (list, tuple)):

TypeError: object of type 'NoneType' has no len()
```
## No error

Running query on primary key (i.e. no blanks) returns a proper data frrame

``` python
#Queries for CCI since Nov 2012
queries = sql.read_frame("select token from vw_queries_lj where query_account_id='34' and from_unixtime(query_created, '%Y-%m-%d') >= '2012-11-01' limit 100;", con)

```
## Expectation

My expected behavior would be that pandas would be able to handle blank columns as character or float, not as NoneType
