[1.5.x] Fixed #19114 -- Fixed LogEntry unicode representation

Thanks niko at neagee.net for the report and Emil Stenstrom for
the patch.
Backport of e0363c688 from master.

tests/regressiontests/admin_util/tests.py

@@ -274,6 +274,10 @@ class UtilTests(unittest.TestCase):
             six.text_type(log_entry).startswith('Deleted ')
         )
 
+        # Make sure custom action_flags works
+        log_entry.action_flag = 4
+        self.assertEqual(six.text_type(log_entry), 'LogEntry Object')
+
     def test_safestring_in_field_label(self):
         # safestring should not be escaped
         class MyForm(forms.Form):