Fixed a place where data provider for a POST in contained None, which cannot be serialized into POST data. Found by Django 2.2 checks.

 - Legacy-Id: 18085

Author: levkowetz

ietf/secr/rolodex/tests.py

@@ -61,7 +61,7 @@ def test_edit_replace_user(self):
         post_data = {
             'name': person.name,
             'ascii': person.ascii,
-            'ascii_short': person.ascii_short,
+            'ascii_short': person.ascii_short or '',
             'user': user.username,
             'email-0-person':person.pk,
             'email-0-address': email.address,