reindex() from string index to DatetimeIndex index returns nan values on Pandas 0.16.2 and 0.16.1
When upgrading to pandas 0.16.2, reindex() from string index to DatetimeIndex index returns nan values.

This test code:

```
indexInit = ["19990101","19990102","19990103"]
values = [1.0,2.5,2.1]
outSeries = Series(values,index=indexInit)
outSeries.reindex(index=DatetimeIndex(outSeries.index))
```

returns:

```
1999-01-01    nan
1999-01-02    nan
1999-01-03    nan
```

Same output on the latest Mac OS X version and also the latest linux version.
We had to downgrade the Pandas version for this to work.
