selinux: ensure we cleanup the internal AVC counters on error in avc_update()

In AVC update we don't call avc_node_kill() when avc_xperms_populate()
fails, resulting in the avc->avc_cache.active_nodes counter having a
false value.  In last patch this changes was missed , so correcting it.

Fixes: fa1aa143 ("selinux: extended permissions for ioctls")
Signed-off-by: Jaihind Yadav <jaihindyadav@codeaurora.org>
Signed-off-by: Ravi Kumar Siddojigari <rsiddoji@codeaurora.org>
[PM: merge fuzz, minor description cleanup]
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/avc.c

@@ -891,7 +891,7 @@ static int avc_update_node(struct selinux_avc *avc,
 	if (orig->ae.xp_node) {
 		rc = avc_xperms_populate(node, orig->ae.xp_node);
 		if (rc) {
-			kmem_cache_free(avc_node_cachep, node);
+			avc_node_kill(avc, node);
 			goto out_unlock;
 		}
 	}