pd.Timestamp behavior/output differences caused by space character placement in the parsed string
#### Code Sample

```python
print(pd.Timestamp('2013, 11, 04'))
print(pd.Timestamp('2013,11, 04'))
print(pd.Timestamp('2013, 11,04'))
```
#### Problem description

Input string changes only by placing spaces differently, but that causes different results. 
Above code results to following:
```
2013-11-04 00:00:00
2013-04-01 00:00:00
2013-11-01 00:00:00
```

I checked current issues opened and did not found anything related to "Timestamp and spaces placement" within parsed string.

I'm running Python 3.6.1 distributed with Anaconda.
Pandas package version: 
pandas                    0.20.1              np112py36_0

#### Expected Output
```
2013-11-04 00:00:00
2013-11-04 00:00:00
2013-11-04 00:00:00
```
#### Output of ``pd.show_versions()``

<details>

INSTALLED VERSIONS
------------------
commit: None
python: 3.6.1.final.0
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 78 Stepping 3, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.20.1
pytest: 3.0.7
pip: 9.0.1
setuptools: 27.2.0
Cython: 0.25.2
numpy: 1.12.1
scipy: 0.19.0
xarray: None
IPython: 5.3.0
sphinx: 1.5.6
patsy: 0.4.1
dateutil: 2.6.1
pytz: 2017.2
blosc: None
bottleneck: 1.2.1
tables: 3.2.2
numexpr: 2.6.2
feather: None
matplotlib: 2.0.2
openpyxl: 2.4.7
xlrd: 1.0.0
xlwt: 1.2.0
xlsxwriter: 0.9.6
lxml: 3.7.3
bs4: 4.6.0
html5lib: 0.999
sqlalchemy: 1.1.9
pymysql: None
psycopg2: None
jinja2: 2.9.6
s3fs: None
pandas_gbq: None
pandas_datareader: None

</details>
