The list of extension names in COGL_EXT_BEGIN should be a zero
separated list of strings which is terminated by an empty string. The
name for the GL_ARB_shader_objects extension was missing the zero
separator so presumably it was relying on the following byte to happen
to be a zero in order not to crash.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit f63381f23fa8b0b17e030561940b8a38efff221f)