Update xvm-devconfig to version 0.80ubuntu2

Requested by glasgall/root@ATHENA.MIT.EDU

diff --git a/xvm-devconfig b/xvm-devconfig
index 48ccd39..df747cf 160000 (submodule)
--- a/xvm-devconfig
+++ b/xvm-devconfig
@@ -1 +1 @@
-Subproject commit 48ccd3963dc798984a799d894d8c0635ec3b099b
+Subproject commit df747cfc315f9c320b2da8a80dd2fcd495add5cb