Since commit 44e7f029
    util: rewrite auto cleanup macros to use glib's equivalent

VIR_AUTOCLEAN is just an alias for g_auto. Use the GLib macros
directly instead of our custom aliases.
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>