Error in test suite for Series.mode
This is on the VM running pandas windows builds.
Windows XP
Python 2.7 32-bit
numpy 1.7.1

```
======================================================================
FAIL: test_mode (pandas.tests.test_series.TestSeries)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\workspace\pandas-windows-test-py27\pandas\tests\test_series.py", line 1727, in test_mode
    assert_series_equal(Series([1, 2, 3]).mode(), Series([], dtype=int))
  File "C:\workspace\pandas-windows-test-py27\pandas\util\testing.py", line 417, in assert_series_equal
    assert_attr_equal('dtype', left, right)
  File "C:\workspace\pandas-windows-test-py27\pandas\util\testing.py", line 401, in assert_attr_equal
    assert_equal(left_attr,right_attr,"attr is not equal [{0}]" .format(attr))
  File "C:\workspace\pandas-windows-test-py27\pandas\util\testing.py", line 384, in assert_equal
    assert a == b, "%s: %r != %r" % (msg.format(a,b), a, b)
AssertionError: attr is not equal [dtype]: dtype('int64') != dtype('int32')
```
