fix in librarian

diff --git a/lib/librarian b/lib/librarian
index 3f61643..5085131 160000 (submodule)
--- a/lib/librarian
+++ b/lib/librarian
@@ -1 +1 @@
-Subproject commit 3f6164384bfd12f173e5f38835ce8a5cfb8b282a
+Subproject commit 50851315ec74af3cad225137935de36904c4c29b