text: Fix regression
text: Fix regression

When the ClutterTextBuffer support inside ClutterText was merged, it
introduced a regression that was identified and fixed in bug 659116.

The optimization to not paint empty ClutterText actors is only valid
is the actor is not editable, or if the cursor is not visible.

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