Fixed another place where None author email needed an extra guard.

 - Legacy-Id: 13573

Author: levkowetz

ietf/bin/generate-draft-aliases

@@ -65,7 +65,7 @@ def get_draft_authors_emails(draft):
     " Get list of authors for the given draft."
 
     # This feels 'correct'; however, it creates fairly large delta
-    return [author.email.email_address() for author in draft.documentauthor_set.all() if author.email.email_address()]
+    return [author.email.email_address() for author in draft.documentauthor_set.all() if author.email and author.email.email_address()]
 
     # This gives fairly small delta compared to current state,
     # however, it seems to be wrong (doesn't check for emails being