glx: Do not leak a XVisualInfo
glx: Do not leak a XVisualInfo

The XVisualInfo we retrieve for the dummy window should be freed after
we used it.

djdeath/clutter,ebassi/clutter,spatulasnout/clutter,jigpu/clutter,nobled/clutter,collects/clutter,djdeath/clutter-multithreaded,djdeath/clutter,spatulasnout/clutter,kerrickstaley/clutter-vala,spatulasnout/clutter,jigpu/clutter,GNOME/clutter,Distrotech/clutter,djdeath/clutter-android,djdeath/clutter-android,djdeath/clutter-android,collects/clutter,djdeath/clutter-android,collects/clutter,djdeath/clutter,ebassi/clutter,kerrickstaley/clutter-vala,Distrotech/clutter,Distrotech/clutter,Distrotech/clutter,rkudiyarov/clutter_osx,nobled/clutter,heysion/clutter-clone,kerrickstaley/clutter-vala,dlespiau/clutter,spatulasnout/clutter,spatulasnout/clutter,jigpu/clutter,Distrotech/clutter,ebassi/clutter,djdeath/clutter,djdeath/clutter-multithreaded,kerrickstaley/clutter-vala,GNOME/clutter,heysion/clutter-clone,djdeath/clutter-multithreaded,collects/clutter,heysion/clutter-clone,rkudiyarov/clutter_osx,jigpu/clutter,GNOME/clutter,jigpu/clutter,Distrotech/clutter,djdeath/clutter-multithreaded,nobled/clutter,collects/clutter,djdeath/clutter,djdeath/clutter-android,dlespiau/clutter,GNOME/clutter,rkudiyarov/clutter_osx,rkudiyarov/clutter_osx,jigpu/clutter,ebassi/clutter,djdeath/clutter,heysion/clutter-clone,GNOME/clutter,ebassi/clutter,heysion/clutter-clone,dlespiau/clutter