Control center shell, panel and breaking compat

[Matthias Clasen <mclasen redhat com>]

So, I put 2.17.90 in rawhide over the last few days
and watched our Fedora menu layout break on the way.

It appears that the switch to using the cc shell by default in
upstream gnome broke the panel menu code for anybody who prefers
to stay with the previous submenu layout for the preferences menu.

I don't think that is acceptable from a compatibility point of view.


Matthias