describe() shows wrong dtype
Pandas version: 0.12.0.
Usecase / how to reproduce:

In ipython, type:
In [1]: x = pd.Series([1, 2])
In [2]: print x.dtype
Out[2]: dtype('int64')
In [3]: x.describe()
Out[3]: 
count    2.000000
mean     1.500000
std      0.707107
min      1.000000
25%      1.250000
50%      1.500000
75%      1.750000
max      2.000000
dtype: float64    <----------------------- This is wrong
