a11y: Fix copy-paste error in state flag notification
a11y: Fix copy-paste error in state flag notification

We weren't checking the removed flag but the added flag for removal
emissions, so what would happen for every state change notification was:
- on state-added, both an "added" and a "removed" event were emitted
- on state-removed, nothing

https://bugzilla.gnome.org/show_bug.cgi?id=694059

ebassi/gtk,msteinert/gtk,Adamovskiy/gtk,Lyude/gtk-,bratsche/gtk-,Adamovskiy/gtk,jessevdk/gtk,jigpu/gtk,grubersjoe/adwaita,grubersjoe/adwaita,ahodesuka/gtk,jigpu/gtk,chergert/gtk,Lyude/gtk-,davidt/gtk,Distrotech/gtk2,Sidnioulz/SandboxGtk,jadahl/gtk,Lyude/gtk-,ebassi/gtk,jessevdk/gtk,alexlarsson/gtk,Sidnioulz/SandboxGtk,msteinert/gtk,chergert/gtk,jadahl/gtk,chergert/gtk,Sidnioulz/SandboxGtk,jessevdk/gtk,chergert/gtk,davidt/gtk,bratsche/gtk-,Adamovskiy/gtk,Sidnioulz/SandboxGtk,ahodesuka/gtk,alexlarsson/gtk,jessevdk/gtk,Distrotech/gtk2,jigpu/gtk,davidgumberg/gtk,davidt/gtk,alexlarsson/gtk,jigpu/gtk,jadahl/gtk,jadahl/gtk,Lyude/gtk-,jessevdk/gtk,msteinert/gtk,jadahl/gtk,ahodesuka/gtk,Sidnioulz/SandboxGtk,Lyude/gtk-,grubersjoe/adwaita,alexlarsson/gtk,Distrotech/gtk2,ahodesuka/gtk,davidgumberg/gtk,jigpu/gtk,ebassi/gtk,davidt/gtk,ahodesuka/gtk,ahodesuka/gtk,alexlarsson/gtk,jadahl/gtk,davidt/gtk,Sidnioulz/SandboxGtk,jessevdk/gtk,Adamovskiy/gtk,davidgumberg/gtk,ebassi/gtk,davidgumberg/gtk,alexlarsson/gtk,davidgumberg/gtk,chergert/gtk,Distrotech/gtk2,grubersjoe/adwaita,alexlarsson/gtk,Distrotech/gtk2,Adamovskiy/gtk,Lyude/gtk-,msteinert/gtk,jigpu/gtk,grubersjoe/adwaita,bratsche/gtk-,ahodesuka/gtk,bratsche/gtk-,Adamovskiy/gtk,Adamovskiy/gtk,Distrotech/gtk2,ahodesuka/gtk,jigpu/gtk,ebassi/gtk,ebassi/gtk,Lyude/gtk-,jigpu/gtk,davidgumberg/gtk,jadahl/gtk,chergert/gtk,grubersjoe/adwaita,davidgumberg/gtk,Adamovskiy/gtk,davidgumberg/gtk,msteinert/gtk,grubersjoe/adwaita,chergert/gtk,davidt/gtk,alexlarsson/gtk,grubersjoe/adwaita,jessevdk/gtk,jadahl/gtk,chergert/gtk,Lyude/gtk-,bratsche/gtk-,msteinert/gtk,bratsche/gtk-