pstree: set ids for helpers

It can be the same with a parent one and the helper will inherit all
parent resources.

Now we can dereference item->ids for all task. It's used in
restore_task_mnt_ns, for example.

Reported-by: Mr Jenkins
Signed-off-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

pstree.c

@@ -478,6 +478,7 @@ static int prepare_pstree_ids(void)
 		helper->pgid = item->sid;
 		helper->pid.virt = item->sid;
 		helper->parent = root_item;
+		helper->ids = root_item->ids;
 		list_add_tail(&helper->sibling, &helpers);
 
 		pr_info("Add a helper %d for restoring SID %d\n",
@@ -596,6 +597,7 @@ static int prepare_pstree_ids(void)
 		helper->pgid = item->pgid;
 		helper->pid.virt = item->pgid;
 		helper->parent = item;
+		helper->ids = item->ids;
 		list_add(&helper->sibling, &item->children);
 		rsti(item)->pgrp_leader = helper;