See
https://git.fedorahosted.org/cgit/lorax.git/commit/?id=0d8397989497261cd8...
Untested, just saw this go by in a lorax run:
No such key 'button-laytout' in schema 'org.gnome.desktop.wm.preferences'
as specified in override file
'/usr/share/glib-2.0/schemas/org.gnome.desktop.wm.preferences.gschema.override';
ignoring override for this key.