refresh libusual

diff --git a/lib b/lib
index 39e497b2b801fe204398bb2972dcc5edb23dd6a8..470ba989f2f2153ecf3747c1dd22ec9176b975c3 160000 (submodule)
--- a/lib
+++ b/lib
@@ -1 +1 @@
-Subproject commit 39e497b2b801fe204398bb2972dcc5edb23dd6a8
+Subproject commit 470ba989f2f2153ecf3747c1dd22ec9176b975c3