actor: Remove default layout-manager
actor: Remove default layout-manager

It's creating more issues than what it's trying to solve. At least for
the time being, let's not set one.

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