winsys-glx: Remove unused variable
winsys-glx: Remove unused variable

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 2cffcae81fd91d97bfa239e8c7c6a5b2cefb2653)

Distrotech/cogl,Distrotech/cogl,Distrotech/cogl,Distrotech/cogl