series with datetime raises pandas.tslib.OutOfBoundsDatetime on value_counts()
I expected that for each value a the number of entries would be returned, instead it throws an OutOfBoundsDatetime although it is not pandas object in first place, but a datetime object. I am aware that the pandas timestamps have a limited time span, however the objects are not timestamps, but datetimes... Thanks!
#### Code Sample, a copy-pastable example if possible

```
import pandas as pd
import datetime
s = pd.Series([datetime.datetime(9999,1,1)])
s.value_counts()
```
#### Expected Output

```
---------------------------------------------------------------------------
OutOfBoundsDatetime                       Traceback (most recent call last)
<ipython-input-7-1b9293e6eb60> in <module>()
----> 1 s.value_counts()

/usr/lib/python2.7/dist-packages/pandas/core/base.pyc in value_counts(self, normalize, sort, ascending, bins, dropna)
    466         from pandas.tseries.api import DatetimeIndex, PeriodIndex
    467         result = value_counts(self, sort=sort, ascending=ascending,
--> 468                               normalize=normalize, bins=bins, dropna=dropna)
    469 
    470         if isinstance(self, PeriodIndex):

/usr/lib/python2.7/dist-packages/pandas/core/algorithms.pyc in value_counts(values, sort, ascending, normalize, bins, dropna)
    318 
    319         if not isinstance(keys, Index):
--> 320             keys = Index(keys)
    321         result = Series(counts, index=keys, name=name)
    322 

/usr/lib/python2.7/dist-packages/pandas/core/index.pyc in __new__(cls, data, dtype, copy, name, fastpath, tupleize_cols, **kwargs)
    177                         tslib.is_timestamp_array(subarr)):
    178                         from pandas.tseries.index import DatetimeIndex
--> 179                         return DatetimeIndex(subarr, copy=copy, name=name, **kwargs)
    180                     elif (inferred.startswith('timedelta') or
    181                           lib.is_timedelta_array(subarr)):

/usr/lib/python2.7/dist-packages/pandas/util/decorators.pyc in wrapper(*args, **kwargs)
     87                 else:
     88                     kwargs[new_arg_name] = new_arg_value
---> 89             return func(*args, **kwargs)
     90         return wrapper
     91     return _deprecate_kwarg

/usr/lib/python2.7/dist-packages/pandas/tseries/index.pyc in __new__(cls, data, freq, start, end, periods, copy, name, tz, verify_integrity, normalize, closed, ambiguous, dtype, **kwargs)
    317                 except ValueError:
    318                     # tz aware
--> 319                     subarr = tools._to_datetime(data, box=False, utc=True)
    320 
    321                 # we may not have been able to convert

/usr/lib/python2.7/dist-packages/pandas/tseries/tools.pyc in _to_datetime(arg, errors, dayfirst, yearfirst, utc, box, format, exact, unit, freq, infer_datetime_format)
    393         return _convert_listlike(arg, box, format, name=arg.name)
    394     elif com.is_list_like(arg):
--> 395         return _convert_listlike(arg, box, format)
    396 
    397     return _convert_listlike(np.array([ arg ]), box, format)[0]

/usr/lib/python2.7/dist-packages/pandas/tseries/tools.pyc in _convert_listlike(arg, box, format, name)
    381                 return DatetimeIndex._simple_new(values, name=name, tz=tz)
    382             except (ValueError, TypeError):
--> 383                 raise e
    384 
    385     if arg is None:

OutOfBoundsDatetime: Out of bounds nanosecond timestamp: 9999-01-01 00:00:00
```
#### output of `pd.show_versions()`

```
INSTALLED VERSIONS
------------------
commit: None
python: 2.7.11.final.0
python-bits: 64
OS: Linux
OS-release: 4.4.0-28-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: de_DE.UTF-8

pandas: 0.17.1
nose: 1.3.7
pip: 8.1.1
setuptools: 20.7.0
Cython: None
numpy: 1.11.0
scipy: 0.17.0
statsmodels: 0.6.1
IPython: 2.4.1
sphinx: None
patsy: 0.4.1
dateutil: 2.4.2
pytz: 2014.10
blosc: None
bottleneck: None
tables: 3.2.2
numexpr: 2.4.3
matplotlib: 1.5.1
openpyxl: 2.3.0
xlrd: 0.9.4
xlwt: 0.7.5
xlsxwriter: None
lxml: 3.5.0
bs4: 4.4.1
html5lib: 0.999
httplib2: 0.9.1
apiclient: None
sqlalchemy: 1.0.11
pymysql: None
psycopg2: None
Jinja2: None


```
