fixed-layout: Use a better quark name
fixed-layout: Use a better quark name

The "fixed-container" name is far too generic, and it may very likely
lead to collisions with application code.

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