cogl-blit: Disable blending when using texture render
cogl-blit: Disable blending when using texture render

When using a pipeline and the journal to blit images between
framebuffers, it should disable blending. Otherwise it will end up
blending the source texture with uninitialised garbage in the
destination texture.

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