kdat: fill kdat by zero-s before initializing it

kerndat_try_load_cache() fills kdat from /run/criu.kdat,
so it will contain some trash, if criu.kdat isn't compatible with the
current version of criu.
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/kerndat.c

@@ -973,6 +973,9 @@ int kerndat_init(void)
 	if (ret <= 0)
 		return ret;
 
+	/* kerndat_try_load_cache can leave some trash in kdat */
+	memset(&kdat, 0, sizeof(kdat));
+
 	preload_socket_modules();
 	preload_netfilter_modules();