`Table.from_rows` fails if no dtype is specified

The shape is wrong, as seen here ((3, 1) instead of (3, )):

(Pdb) l
189              assert np.allclose([4, 5, 6], t.b)
190
191          def test_from_rows_with_colnames(self):
192              t = Table.from_rows([[1, 2], [3, 4], [5, 6]], colnames=['a', 'b'])
193              import pdb; pdb.set_trace()
194  ->            assert np.allclose([1, 3, 5], t.a)
195              assert np.allclose([2, 4, 6], t.b)
196
197          def test_fromrows(self):
198              dlist = [
199                  [1, 2, 3],
(Pdb) t.dtype
dtype((numpy.record, [('a', '<i8'), ('b', '<i8')]))
(Pdb) t.shape
(3, 1)