Make this less stateful https://bugzilla.gnome.org/show_bug.cgi?id=677586
Create the potentially empty directory when we need to, not when we don't. https://bugzilla.gnome.org/show_bug.cgi?id=677586
This keeps all UI out of the extension system, leaving it strictly for loading and unloading extensions. https://bugzilla.gnome.org/show_bug.cgi?id=677586