refresh libusual

diff --git a/lib b/lib
index 7fe98a4480242b19ce9e9d53bd3341bd3bf38823..ff2257a0b54e051622a348968ec2f09334b7f65c 160000 (submodule)
--- a/lib
+++ b/lib
@@ -1 +1 @@
-Subproject commit 7fe98a4480242b19ce9e9d53bd3341bd3bf38823
+Subproject commit ff2257a0b54e051622a348968ec2f09334b7f65c