Dividing Series of Decimal objects by Decimal raises AttributeError
This worked fine with pandas 0.15:

``` python
In [24]: import pandas as pd
In [25]: from decimal import Decimal
In [26]: s = pd.Series([Decimal(10)] * 10)
In [27]: s / Decimal(5)
Out[27]: 
0    2
1    2
2    2
3    2
4    2
5    2
6    2
7    2
8    2
9    2
dtype: object
```

When I use 0.16.0, it raises:

```
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-29-f6e1a63d5a28> in <module>()
----> 1 s / Decimal(5)

/home/jck/anaconda/lib/python2.7/site-packages/pandas/core/ops.pyc in wrapper(left, right, name)
    530             if hasattr(lvalues, 'values'):
    531                 lvalues = lvalues.values
--> 532             return left._constructor(wrap_results(na_op(lvalues, rvalues)),
    533                                      index=left.index, name=left.name,
    534                                      dtype=dtype)

/home/jck/anaconda/lib/python2.7/site-packages/pandas/core/ops.pyc in na_op(x, y)
    483             result, changed = com._maybe_upcast_putmask(result, ~mask, np.nan)
    484 
--> 485         result = com._fill_zeros(result, x, y, name, fill_zeros)
    486         return result
    487 

/home/jck/anaconda/lib/python2.7/site-packages/pandas/core/common.pyc in _fill_zeros(result, x, y, name, fill)
   1407         y = np.array(y)
   1408 
-> 1409     if is_integer_dtype(y):
   1410 
   1411         if (y == 0).any():

/home/jck/anaconda/lib/python2.7/site-packages/pandas/core/common.pyc in is_integer_dtype(arr_or_dtype)
   2448 
   2449 def is_integer_dtype(arr_or_dtype):
-> 2450     tipo = _get_dtype_type(arr_or_dtype)
   2451     return (issubclass(tipo, np.integer) and
   2452             not issubclass(tipo, (np.datetime64, np.timedelta64)))

/home/jck/anaconda/lib/python2.7/site-packages/pandas/core/common.pyc in _get_dtype_type(arr_or_dtype)
   2439     elif isinstance(arr_or_dtype, CategoricalDtype):
   2440         return CategoricalDtypeType
-> 2441     return arr_or_dtype.dtype.type
   2442 
   2443 

AttributeError: 'Decimal' object has no attribute 'dtype'
```

```
INSTALLED VERSIONS
------------------
commit: None
python: 2.7.9.final.0
python-bits: 64
OS: Linux
OS-release: 3.13.0-24-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8

pandas: 0.16.0
nose: 1.3.4
Cython: 0.21
numpy: 1.9.2
scipy: 0.14.0
statsmodels: 0.5.0
IPython: 2.2.0
sphinx: 1.2.3
patsy: 0.3.0
dateutil: 2.4.2
pytz: 2015.2
bottleneck: None
tables: 3.1.1
numexpr: 2.3.1
matplotlib: 1.4.0
openpyxl: 1.8.5
xlrd: 0.9.3
xlwt: 0.7.5
xlsxwriter: 0.5.7
lxml: 3.4.0
bs4: 4.3.2
html5lib: None
httplib2: None
apiclient: None
sqlalchemy: 0.9.7
pymysql: None
psycopg2: None
```
