make test name consistent with the rest of the file

Lib/test/test_exceptions.py

@@ -763,7 +763,7 @@ class ExceptionTests(unittest.TestCase):
             pass
         self.assertEqual(e, (None, None, None))
 
-    def testUnicodeChangeAttributes(self):
+    def test_unicode_change_attributes(self):
         # See issue 7309. This was a crasher.
 
         u = UnicodeEncodeError('baz', 'xxxxx', 1, 5, 'foo')