Bug 1003843 - Follow up to Bug 951676 - [Messages][Refresh] Add specific image in case of more than one recipient in the list threads. r=schung

actually, I'd like to display them also when we have a contact, because currently, when we load the app, we see:

* all threads are added
* after some time, threads with known contacts have a white space on the right; contacts without pictures have the blue disk quite immediately, but pictures for contacts with pictures are displayed after a few seconds (because it takes some time to decode and display them)

Therefore I think it could be a good idea to display the blue disk behind the contact's picture, I think it's easier on the eye. What do you think?