Series with datetime64 dtype causes failure in dict passed to DataFrame
works:

```
In [9]: d = pandas.DataFrame({'A': 'foo', 'B': ts.values}, index=dr)

In [10]: d.head()
Out[10]: 
              A                   B
2011-01-07  foo 2011-01-07 00:00:00
2011-01-14  foo 2011-01-14 00:00:00
2011-01-21  foo 2011-01-21 00:00:00
2011-01-28  foo 2011-01-28 00:00:00
2011-02-04  foo 2011-02-04 00:00:00
```

does not work:

```
d = pandas.DataFrame({'A': 'foo', 'B': ts.values}, index=dr)
```
