egl: Rename backend constructor function
egl: Rename backend constructor function

Otherwise the build will fail.

GNOME/clutter,Distrotech/clutter,GNOME/clutter,Distrotech/clutter,Distrotech/clutter,GNOME/clutter,Distrotech/clutter,GNOME/clutter,GNOME/clutter,Distrotech/clutter,Distrotech/clutter