Unbreak GtkComboBox::button-sensitivity
Unbreak GtkComboBox::button-sensitivity

Fixed the button-sensivity patch done to GtkComboBox to account for
changes in appearance (changes to the appears-as-list style property).
Also, in list-mode, the event box that has been created below the cell
view also needs to have its sensitivity updated.

bratsche/gtk-,Sidnioulz/SandboxGtk,chergert/gtk,chipx86/gtk,Lyude/gtk-,chipx86/gtk,Distrotech/gtk,grubersjoe/adwaita,chergert/gtk,alexlarsson/gtk,jadahl/gtk,Distrotech/gtk2,Adamovskiy/gtk,davidt/gtk,grubersjoe/adwaita,ebassi/gtk,johne53/MB3Gtk-2,jadahl/gtk,Lyude/gtk-,davidgumberg/gtk,Unity-Technologies/gtk,Lyude/gtk-,ahodesuka/gtk,chergert/gtk,grubersjoe/adwaita,alexlarsson/gtk,ahodesuka/gtk,Sidnioulz/SandboxGtk,chergert/gtk,grubersjoe/adwaita,bratsche/gtk-,ahodesuka/gtk,alexlarsson/gtk,ebassi/gtk,alexlarsson/gtk,msteinert/gtk,davidgumberg/gtk,bratsche/gtk-,davidgumberg/gtk,jadahl/gtk,ahodesuka/gtk,jadahl/gtk,bratsche/gtk-,jadahl/gtk,Adamovskiy/gtk,davidgumberg/gtk,davidgumberg/gtk,jigpu/gtk,chipx86/gtk,ebassi/gtk,jessevdk/gtk,chipx86/gtk,Distrotech/gtk2,jessevdk/gtk,alexlarsson/gtk,simokivimaki/gtk,jessevdk/gtk,davidt/gtk,bratsche/gtk-,jadahl/gtk,grubersjoe/adwaita,jadahl/gtk,Adamovskiy/gtk,jessevdk/gtk,davidt/gtk,davidgumberg/gtk,nacho/gtk-,simokivimaki/gtk,Distrotech/gtk,Sidnioulz/SandboxGtk,Adamovskiy/gtk,Unity-Technologies/gtk,simokivimaki/gtk,jigpu/gtk,jessevdk/gtk,alexlarsson/gtk,Sidnioulz/SandboxGtk,johne53/MB3Gtk-2,nacho/gtk-,msteinert/gtk,chergert/gtk,jigpu/gtk,davidt/gtk,Distrotech/gtk2,jigpu/gtk,Adamovskiy/gtk,Distrotech/gtk2,Adamovskiy/gtk,msteinert/gtk,ebassi/gtk,msteinert/gtk,davidgumberg/gtk,jigpu/gtk,chergert/gtk,simokivimaki/gtk,simokivimaki/gtk,jigpu/gtk,nacho/gtk-,Distrotech/gtk,grubersjoe/adwaita,nacho/gtk-,johne53/MB3Gtk-2,jigpu/gtk,grubersjoe/adwaita,bratsche/gtk-,chergert/gtk,ahodesuka/gtk,jessevdk/gtk,msteinert/gtk,davidt/gtk,Distrotech/gtk2,Distrotech/gtk,Adamovskiy/gtk,Lyude/gtk-,ahodesuka/gtk,Lyude/gtk-,davidt/gtk,ahodesuka/gtk,johne53/MB3Gtk-2,chergert/gtk,Sidnioulz/SandboxGtk,Lyude/gtk-,jadahl/gtk,chipx86/gtk,johne53/MB3Gtk-2,simokivimaki/gtk,jigpu/gtk,Sidnioulz/SandboxGtk,Unity-Technologies/gtk,Adamovskiy/gtk,Distrotech/gtk,alexlarsson/gtk,msteinert/gtk,Unity-Technologies/gtk,Distrotech/gtk2,ebassi/gtk,Lyude/gtk-,grubersjoe/adwaita,davidgumberg/gtk,alexlarsson/gtk,Unity-Technologies/gtk,ahodesuka/gtk,jessevdk/gtk,ebassi/gtk,Lyude/gtk-,nacho/gtk-