BUG: allow describe() for on boolean-only columns
I know I can obtain the expected output by using `include=['bool']`, but that feels bad to me as a user. I want `describe()` to know that I'm only asking for boolean columns and not freak out.

Thank you!
#### Code Sample, a copy-pastable example if possible

``` python
>>> test_df = pd.DataFrame({'test_ind_1': [False, False, True, True, False, True , True, False],  'test_ind_2': [False, True, True, False, False, True, True,True]})
>>> test_df.describe()
```
#### Expected Output

``` python
│       test_ind_1 test_ind_2
│count           8          8
│unique          2          2
│top          True       True
│freq            4          5
```
#### Actual output

``` python
ValueError: No objects to concatenate
```
#### output of `pd.show_versions()`

``` python
INSTALLED VERSIONS
------------------
commit: None
python: 2.7.12.final.0
python-bits: 64
OS: Linux
OS-release: 3.10.0-327.18.2.el7.x86_64
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8

pandas: 0.18.1
nose: 1.3.7
pip: 8.1.2
setuptools: 23.0.0
Cython: 0.22.1
numpy: 1.11.1
scipy: 0.17.1
statsmodels: 0.6.1
xarray: None
IPython: 5.0.0
sphinx: 1.3.1
patsy: 0.3.0
dateutil: 2.4.1
pytz: 2016.6.1
blosc: None
bottleneck: 1.0.0
tables: 3.2.0
numexpr: 2.4.3
matplotlib: 1.5.1
openpyxl: 1.8.5
xlrd: 0.9.3
xlwt: 1.0.0
xlsxwriter: 0.7.3
lxml: 3.4.4
bs4: 4.3.2
html5lib: None
httplib2: None
apiclient: None
sqlalchemy: 1.0.5
pymysql: None
psycopg2: None
jinja2: 2.8
boto: 2.38.0
pandas_datareader: None
```
