BF: remove scipy decorator from mixin tests

I was using the decorator to say that that tests need scipy inside the
scaling tests mixin, instead of in the main test function for Spm99,
where this is actually true.  Hence tests were being skipped for Nifti1,
Nifti2 if scipy missing, when then need not be skipped.

Author: matthew-brett

nibabel/tests/test_spm99analyze.py

@@ -319,7 +319,6 @@ def test_int_int_scaling(self):
         img_rt = bytesio_round_trip(img)
         assert_array_equal(img_rt.get_data(), np.clip(arr, 0, 255))
 
-    @scipy_skip
     def test_no_scaling(self):
         # Test writing image converting types when not calculating scaling
         img_class = self.image_class
@@ -368,7 +367,6 @@ def test_write_scaling(self):
         ):
             self._check_write_scaling(slope, inter, e_slope, e_inter)
 
-    @scipy_skip
     def test_nan2zero_range_ok(self):
         # Check that a floating point image with range not including zero gets
         # nans scaled correctly
@@ -416,6 +414,10 @@ class TestSpm99AnalyzeImage(test_analyze.TestAnalyzeImage, ScalingMixin):
 
     test_write_scaling = scipy_skip(ScalingMixin.test_write_scaling)
 
+    test_no_scaling = scipy_skip(ScalingMixin.test_no_scaling)
+
+    test_nan2zero_range_ok = scipy_skip(ScalingMixin.test_nan2zero_range_ok)
+
     @scipy_skip
     def test_mat_read(self):
         # Test mat file reading and writing for the SPM analyze types