BUG: Series.reindex using TimedeltaIndex/PeriodIndex/DatetimeIndex as index will erase the data to np.NaN
When we want to reindex an existing Series using TimedeltaIndex/PeriodIndex/DatetimeIndex,
the result will have np.NaN as data

``` python
In [1]: import pandas as pd

In [2]: # Case of `TimedeltaIndex`

In [3]: a = pd.Series(['A'] * 3)

In [4]: t_d_idx = pd.to_timedelta([0, 10, 20], unit='s')

In [5]: type(t_d_idx)
Out[5]: pandas.tseries.tdi.TimedeltaIndex

In [6]: a
Out[6]: 
0    A
1    A
2    A
dtype: object

In [7]: a.reindex(index=t_d_idx)
Out[7]: 
00:00:00    NaN
00:00:10    NaN
00:00:20    NaN
dtype: object

In [8]: # Case of `PeriodIndex`

In [9]: b = pd.Series(['B'] * 3)

In [10]: p_idx = pd.period_range('2010-01', '2010-03', freq='M')

In [11]: type(p_idx)
Out[11]: pandas.tseries.period.PeriodIndex

In [12]: b
Out[12]: 
0    B
1    B
2    B
dtype: object

In [13]: b.reindex(index=p_idx)
Out[13]: 
2010-01    NaN
2010-02    NaN
2010-03    NaN
Freq: M, dtype: object

In [14]: # Case of `DatetimeIndex`

In [15]: c = pd.Series(['C'] * 3)

In [16]: d_t_idx = pd.DatetimeIndex(start='2016-1-1', end='2016-4-1', freq='M')

In [17]: type(d_t_idx)
Out[17]: pandas.tseries.index.DatetimeIndex

In [18]: c
Out[18]: 
0    C
1    C
2    C
dtype: object

In [19]: c.reindex(index=d_t_idx)
Out[19]: 
2016-01-31    NaN
2016-02-29    NaN
2016-03-31    NaN
Freq: M, dtype: object

```

Even when you want to reindex a Series which already have DatetimeIndex as index

``` Python

In [20]: ts = pd.Series(
   ....:         range(3),
   ....:         index=pd.DatetimeIndex(
   ....:                 start='2016-2-1',
   ....:                 end='2016-2-22',
   ....:                 freq='W'
   ....:               )
   ....:         )

In [21]: type(ts.index)
Out[21]: pandas.tseries.index.DatetimeIndex

In [22]: ts
Out[22]: 
2016-02-07    0
2016-02-14    1
2016-02-21    2
Freq: W-SUN, dtype: int64

In [23]: ts.reindex(index=d_t_idx)
Out[23]: 
2016-01-31   NaN
2016-02-29   NaN
2016-03-31   NaN
Freq: M, dtype: float64

```

Is this what we expect Series.index should behave?
