deform-effect: Don't use deprecated API
deform-effect: Don't use deprecated API

The ClutterOffscreenEffect.get_target_size() method has been deprecated,
and replaced by the get_target_rect() one. We can easily switch to the
latter, and avoid the deprecation warning.

https://bugzilla.gnome.org/show_bug.cgi?id=670004

GNOME/clutter,jigpu/clutter,heysion/clutter-clone,djdeath/clutter,ebassi/clutter,heysion/clutter-clone,collects/clutter,ebassi/clutter,collects/clutter,Distrotech/clutter,heysion/clutter-clone,collects/clutter,ebassi/clutter,jigpu/clutter,djdeath/clutter,heysion/clutter-clone,djdeath/clutter-android,djdeath/clutter-android,djdeath/clutter,heysion/clutter-clone,ebassi/clutter,jigpu/clutter,GNOME/clutter,GNOME/clutter,Distrotech/clutter,Distrotech/clutter,GNOME/clutter,djdeath/clutter,Distrotech/clutter,collects/clutter,djdeath/clutter,GNOME/clutter,djdeath/clutter,ebassi/clutter,Distrotech/clutter,djdeath/clutter-android,djdeath/clutter-android,jigpu/clutter,Distrotech/clutter,jigpu/clutter,collects/clutter,jigpu/clutter,djdeath/clutter-android