Update invirt-web to version 0.1.56

Requested by mitchb/root@ATHENA.MIT.EDU

diff --git a/invirt-web b/invirt-web
index cf60fd3..dbabdbd 160000 (submodule)
--- a/invirt-web
+++ b/invirt-web
@@ -1 +1 @@
-Subproject commit cf60fd3bc04d5ea552c4d2b16858da20135a6498
+Subproject commit dbabdbd3df5e4a8b9f716689777f7d5c74bc7a92