Make readonly members defined in C throw an AttributeError on modification. This brings them into sync with Python-level attributes. Fixes bug #1687163.
diff --git a/Lib/test/test_csv.py b/Lib/test/test_csv.py
index 46361c8..2cdc807 100644
--- a/Lib/test/test_csv.py
+++ b/Lib/test/test_csv.py
@@ -53,8 +53,8 @@
         self.assertEqual(obj.dialect.skipinitialspace, False)
         self.assertEqual(obj.dialect.strict, False)
         # Try deleting or changing attributes (they are read-only)
-        self.assertRaises(TypeError, delattr, obj.dialect, 'delimiter')
-        self.assertRaises(TypeError, setattr, obj.dialect, 'delimiter', ':')
+        self.assertRaises(AttributeError, delattr, obj.dialect, 'delimiter')
+        self.assertRaises(AttributeError, setattr, obj.dialect, 'delimiter', ':')
         self.assertRaises(AttributeError, delattr, obj.dialect, 'quoting')
         self.assertRaises(AttributeError, setattr, obj.dialect,
                           'quoting', None)