treeview: cleanup treeview state selectors
treeview: cleanup treeview state selectors

Don't specify both GtkTreeView and GtkTreeView.view, since we already
specify .view. This also fixes cell renderers that specify different
backgrounds for a specific state, like GtkCellRendererProgress, as
reported in

https://bugzilla.gnome.org/show_bug.cgi?id=673840

ChrisCummins/gnome-themes-standard,rgcjonas/adwaita-semidark,magcius/gnome-themes-standard,rgcjonas/adwaita-semidark,magcius/gnome-themes-standard,Distrotech/gnome-themes-standard,cosimoc/gnome-themes-standard,magcius/gnome-themes-standard,cosimoc/gnome-themes-standard,rgcjonas/adwaita-semidark,ChrisCummins/gnome-themes-standard,ChrisCummins/gnome-themes-standard,DoctorJellyface/gnome-themes-standard,Distrotech/gnome-themes-standard,ChrisCummins/gnome-themes-standard,DoctorJellyface/gnome-themes-standard,cosimoc/gnome-themes-standard,ChrisCummins/gnome-themes-standard,rgcjonas/adwaita-semidark,cosimoc/gnome-themes-standard