object: use GLib's DestroyNotify if compiled with GLib
object: use GLib's DestroyNotify if compiled with GLib

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit b53de3352192618d33400363040d79cb2bc66fb0)

djdeath/cogl,djdeath/cogl,djdeath/cogl