Update xmltooling for build problem

diff --git a/shibboleth/xmltooling b/shibboleth/xmltooling
index fd53289..50b34ac 160000 (submodule)
--- a/shibboleth/xmltooling
+++ b/shibboleth/xmltooling
@@ -1 +1 @@
-Subproject commit fd5328983f712e9b607d3d364987332e276fc707
+Subproject commit 50b34ac26c548ddf812855a193bdb703c40bc4fc