Reindex function applied to DataFrame over columns ignores method
#### Code Sample

```python

>>> df = pd.DataFrame(data=[[11, 12, 13], [21, 22, 23], [31, 32, 33]],
                      index=[1, 3, 5],
                      columns=[1, 3, 5],
                      dtype=float)
>>> print(df)
      1     3     5
1  11.0  12.0  13.0
3  21.0  22.0  23.0
5  31.0  32.0  33.0

# Applying the reindex function to the columns, with the "ffill" method:
>>> print(df.reindex(columns=range(7), method='ffill'))
    0     1   2     3   4     5   6
1 NaN  11.0 NaN  12.0 NaN  13.0 NaN
3 NaN  21.0 NaN  22.0 NaN  23.0 NaN
5 NaN  31.0 NaN  32.0 NaN  33.0 NaN

# Workaround to get the expected output:
>>> print(df.T.reindex(index=range(7), method='ffill').T)
    0     1     2     3     4     5     6
1 NaN  11.0  11.0  12.0  12.0  13.0  13.0
3 NaN  21.0  21.0  22.0  22.0  23.0  23.0
5 NaN  31.0  31.0  32.0  32.0  33.0  33.0
```

#### Problem description

I want to apply the `reindex` function to the columns using the `"ffill"` method, but the holes are filled with NaN. The workaround is to transpose the DataFrame, apply the function and then transpose again.

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

<details>

INSTALLED VERSIONS
------------------
commit: None
python: 2.7.12.final.0
python-bits: 64
OS: Darwin
OS-release: 16.1.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: en_US.UTF-8
LANG: en_US.UTF-8

pandas: 0.18.1
nose: None
pip: 9.0.1
setuptools: 27.2.0
Cython: None
numpy: 1.11.1
scipy: None
statsmodels: None
xarray: None
IPython: 5.1.0
sphinx: None
patsy: None
dateutil: 2.6.0
pytz: 2016.10
blosc: None
bottleneck: None
tables: None
numexpr: None
matplotlib: None
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: None
html5lib: None
httplib2: None
apiclient: None
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.8
boto: 2.38.0
pandas_datareader: None
</details>
