fix z_camera calcualtion in gles/cogl
fix z_camera calcualtion in gles/cogl

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