Childless Comment Not Deleted

[PeterBParker]

Description of Symptom
When a user comments and then replies to their own comment and no one else does, when they go to delete their account, the original comment will persist as a "This comment was deleted." It would be nice if the database updated whether or not the comment has children as each comment is deleted.

Steps to Reproduce

1. Write a new comment as User A
2. Respond to the comment as User A
3. Delete User A's account

If no one else has replied to his comment, the comment will persist with no children as a "This comment was deleted" comment instead of disappearing.