action: ensure compatibility with glib 2.28 and 2.30
action: ensure compatibility with glib 2.28 and 2.30

The set_state virtual function of GAction was renamed to change_state in
glib 2.30.

jonnylamb/mx,clutter-project/mx,clutter-project/mx,jonnylamb/mx,clutter-project/mx,clutter-project/mx,pwithnall/mx,pwithnall/mx,jonnylamb/mx,jonnylamb/mx,pwithnall/mx,pwithnall/mx