AssertionError with DataFrame.from_records() when it should create column of nulls
https://github.com/pandas-dev/pandas/blob/cb00deb94500205fcb27a33cc1d0df79a9727f8b/pandas/core/frame.py#L1430-L1556

I passed a list of data with 5 columns but a column header list of 6 items. The documentation for `pd.DataFrame.from_records()` says:

> any names not found in the data will become all-NA columns

However, instead I get:
```python
AssertionError: 6 columns passed, passed data has 5 columns
```

If I am interpreting this wrong or using this method the wrong way, I'm welcome to any suggestions too. Code to reproduce: 
```python
>>> import pandas as pd
>>> data = [list(range(1,6))]
>>> data
[[1, 2, 3, 4, 5]]
>>> col_headers = 'A B C D E F'.split()
>>> col_headers
['A', 'B', 'C', 'D', 'E', 'F']
>>> df = pd.DataFrame.from_records(data=data, columns=col_headers)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/dtorkelson/miniconda3/envs/branker/lib/python3.7/site-packages/pandas/core/frame.py", line 1512, in from_records
    coerce_float=coerce_float)
  File "/Users/dtorkelson/miniconda3/envs/branker/lib/python3.7/site-packages/pandas/core/internals/construction.py", line 404, in to_arrays
    dtype=dtype)
  File "/Users/dtorkelson/miniconda3/envs/branker/lib/python3.7/site-packages/pandas/core/internals/construction.py", line 436, in _list_to_arrays
    coerce_float=coerce_float)
  File "/Users/dtorkelson/miniconda3/envs/branker/lib/python3.7/site-packages/pandas/core/internals/construction.py", line 492, in _convert_object_array
    con=len(content)))
AssertionError: 6 columns passed, passed data had 5 columns
>>> col_headers.pop(5)
'F'
>>> df = pd.DataFrame.from_records(data=data, columns=col_headers)
>>> df
   A  B  C  D  E
0  1  2  3  4  5
``` 

The extra column name is passed because this code is being used to create many dataframes in a loop, which are being appended to each other. Many have data in the sixth column, but for those that don't, I was hoping (and thinking) that pandas would fill it in with nulls.