xwayland/eglstream: Log when GL_OES_EGL_image is missing

That will dramatically affect performance, might as well log when we
cannot use GL_OES_EGL_image with the NVIDIA closed-source driver.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
5 jobs for xwayland-eglstream-glvnd in 20 minutes and 54 seconds (queued for 14 seconds)