0.12: Strange Series.reindex() error
Using 0.12 production version.

I have a series res that is indexed by strings:

```
res.index.shape
```

> (2578L,)

```
res.head()
```

> stock_id
> 000312     -0.000198
> 00036110    0.000142
> 00101J10   -0.000229
> 00103110   -0.000170
> 00105510   -0.001236
> dtype: float64

I have a DataFrame test also indexed by stock_id. res has some stock_ids missing compared to test. 

```
test.index.shape
```

> (2607L,)

```
test.index[:5]
```

> Index([u'000312', u'00036110', u'00101J10', u'00103110', u'00105510'], dtype=object)

I am trying to add res as a column to test. For that, I am trying to reindex res:

```
res.reindex(test.index)
```

> ---------------------------------------------------------------------------
> AssertionError                            Traceback (most recent call last)
> <ipython-input-148-265ae924cbbf> in <module>()
> ----> 1 res.reindex(test.index)
> 
> C:\Python27\lib\site-packages\pandas\core\series.pyc in reindex(self, index, method, level, fill_value, limit, copy, takeable)
>    2644 
>    2645         # GH4246 (dispatch to a common method with frame to handle possibly duplicate index)
> -> 2646         return self._reindex_with_indexers(new_index, indexer, copy=copy, fill_value=fill_value)
>    2647 
>    2648     def _reindex_with_indexers(self, index, indexer, copy, fill_value):
> 
> C:\Python27\lib\site-packages\pandas\core\series.pyc in _reindex_with_indexers(self, index, indexer, copy, fill_value)
>    2648     def _reindex_with_indexers(self, index, indexer, copy, fill_value):
>    2649         new_values = com.take_1d(self.values, indexer, fill_value=fill_value)
> -> 2650         return Series(new_values, index=index, name=self.name)
>    2651 
>    2652     def reindex_axis(self, labels, axis=0, **kwargs):
> 
> C:\Python27\lib\site-packages\pandas\core\series.pyc in **new**(cls, data, index, dtype, name, copy)
>     490         else:
>     491             subarr = subarr.view(Series)
> --> 492         subarr.index = index
>     493         subarr.name = name
>     494 
> 
> C:\Python27\lib\site-packages\pandas\lib.pyd in pandas.lib.SeriesIndex.**set** (pandas\lib.c:29092)()
> 
> AssertionError: Index length did not match values

This is strange as I thought this was exactly the reason for reindex. For example, I can easily do this:

```
x = Series(range(10))
x.reindex(range(20))
```

Why doesn't it work in my case?
