criu: action-scripts -- Don't access @root_item_pid if not present

It might be nil on predump, so dereference only when present.
Signed-off-by: Cyrill Gorcunov <gorcunov@virtuozzo.com>
Acked-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/action-scripts.c

@@ -48,11 +48,13 @@ int run_scripts(enum script_actions act)
 		return -1;
 	}
 
+	if (root_item) {
 		snprintf(root_item_pid, sizeof(root_item_pid), "%d", root_item->pid.real);
 		if (setenv("CRTOOLS_INIT_PID", root_item_pid, 1)) {
 			pr_perror("Can't set CRTOOLS_INIT_PID=%s", root_item_pid);
 			return -1;
 		}
+	}
 
 	list_for_each_entry(script, &opts.scripts, node) {
 		if (script->path == SCRIPT_RPC_NOTIFY) {