pixel-array: Remove some benign variables
pixel-array: Remove some benign variables

There were some completely unused static global variables declared in
cogl-pixel-array.c which this patch removes.

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