Changing profile picture updates activity comments picture but not actor picture

When uploading a new profile picture the UI should be updated everywhere the old picture was displayed. Currently there is a regression where the activity actor picture isn't updated after uploading the picture. In the screenshot you'll see that general ackbar is still set as my profile picture and hasn't been updated to a selfie.

![screen shot 2014-06-17 at 16 25 38](https://cloud.githubusercontent.com/assets/218391/3302368/ba9242fc-f633-11e3-9b12-468fe192a42a.png)

Looks like the ID is coming back as a link to the user API endpoint from the backend feed. My impression is that's a bug, I'll dig deeper. cc @mrvisser