Generated Avatars Do Not Show on Comment Moderation Page

[Mike9824]

I upgraded to 3.9.1 and on the comment moderation page in wp-admin, user avatars now all show Mystery Man instead of the automatically generated images shown on the comment page.

Steps to reproduce:

1. Go to Settings -> Discussion
2. Tick 'Show Avatars'
3. Select a generated Default Avatar and save changes
4. Go to the Comment Moderation page
5. See non-gravatar users have a Mystery Man avatar instead of a generated avatar.

The generated avatars still show on the comment pages, just not the moderate comment page in wp-admin.

Another user in #wordpress on irc.freenode.net also experienced this when following the steps after I brought it up there.

[SergeyBiryukov]

Not showing auto-generated Gravatars for comment authors in the admin was an intended change in #7054 to make comment moderation easier.

This is a duplicate of #25764. There's a workaround plugin attached to that ticket.