Silence another compiler warning
Silence another compiler warning

collects/cogl,Distrotech/cogl,collects/cogl,spatulasnout/cogl,spatulasnout/cogl,Distrotech/cogl,djdeath/cogl-android,djdeath/cogl,djdeath/cogl,gcampax/cogl,Distrotech/cogl,djdeath/cogl-android,djdeath/cogl-android,gcampax/cogl,Distrotech/cogl,gcampax/cogl,djdeath/cogl,gcampax/cogl