'Regression test for an issue that appeared after SVN r2412.'

def test_update_rvkc_2(self):

    h = fits.Header()
    h['D2IM1.EXTVER'] = 1
    assert (h['D2IM1.EXTVER'] == 1.0)
    h['D2IM1.EXTVER'] = 2
    assert (h['D2IM1.EXTVER'] == 2.0)
