update mezzanine-agenda

diff --git a/lib/mezzanine-agenda b/lib/mezzanine-agenda
index 383ca0db02232cf761e1e489ed1315a58cb95693..5f6399bd68793c8a16048e59988ce4a60daa3c8e 160000 (submodule)
--- a/lib/mezzanine-agenda
+++ b/lib/mezzanine-agenda
@@ -1 +1 @@
-Subproject commit 383ca0db02232cf761e1e489ed1315a58cb95693
+Subproject commit 5f6399bd68793c8a16048e59988ce4a60daa3c8e