Update xvm-devconfig to version 0.90

Requested by mitchb/root@ATHENA.MIT.EDU

diff --git a/xvm-devconfig b/xvm-devconfig
index 0d4b811..9fe70c2 160000 (submodule)
--- a/xvm-devconfig
+++ b/xvm-devconfig
@@ -1 +1 @@
-Subproject commit 0d4b8117ef84d9b4395777666ccf2e6c4ef79b43
+Subproject commit 9fe70c2cad9148446342a1fbf6bcb5b43a5e23f0