Comment 4 for bug 1395667

This turned out to be much more simple than I thought. Since trusty (at least), python-appindicator is no longer installed as part of the default environment. I will add it as a recommended package and also change the default settings to not minimize to the system tray so that if the icon doesn't appear at all (unity without python-appindicator or some other environment with no system tray) you will have to make an explicit config change to make the GUI hide itself. I will leave figuring out why it doesn't know that it's not showing up in the systray for a separate bug.

For now, simply "sudo apt-get python-appindicator" and the unity indicator will start showing up again.