Aggregating groupby with multiple functions all return the same value
So, I want to aggregate a grouped by object by two criterion: count of observations, and count of nonzero observations:
```python
# nonzero counts by shipment number
data.groupby(['Shipment number'])['Shipment number']
	.agg({'count' : lambda x: x.count(), 
	      'nonzero' : lambda x: x.nonzero()[0].size})
	.sort_values('count')

```
#### Problem description

While this code is referenced in [issue 7186](https://github.com/pandas-dev/pandas/issues/7186), and the issue is closed, there is a bug: all the output columns are the same. That is evident even in issue 7186, and I'm shocked how nobody picked it up.

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

commit: None
python: 2.7.6.final.0
python-bits: 64
OS: Linux
OS-release: 4.4.0-31-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8

pandas: 0.20.3
pytest: None
pip: 9.0.1
setuptools: 36.0.1
Cython: None
numpy: 1.13.1
scipy: 0.19.1
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: 2.0.2
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: 4.4.1
html5lib: 1.0b3
sqlalchemy: 1.0.14
pymysql: None
psycopg2: 2.7.1 (dt dec pq3 ext lo64)
jinja2: 2.7.3
s3fs: None
pandas_gbq: None
pandas_datareader: None

</details>
