refresh libusual

diff --git a/lib b/lib
index e67d8210bfe4ec342654160e98a7ae33d5d31257..7250ab4641689ff32853f198702c35b9f8609f56 160000 (submodule)
--- a/lib
+++ b/lib
@@ -1 +1 @@
-Subproject commit e67d8210bfe4ec342654160e98a7ae33d5d31257
+Subproject commit 7250ab4641689ff32853f198702c35b9f8609f56