For some reason Unity doesn't like the GtkMenu which is built
from the GMenuModel from a .ui file. This patch creates the menu
via code and fixes these issues in the status icon menu in Unity:
- the "Show Ring" checkbox is not consistent when the window is
  closed via the 'x'
- the 'Quit' menu item was being rendered with a checkbox

Change-Id: I9fe488a88c881ac795b93e88f4925096a4acf361
Tuleap: #370