Update xvm-prodconfig to version 1.1.48~migration6

Requested by glasgall/root@ATHENA.MIT.EDU

diff --git a/xvm-prodconfig b/xvm-prodconfig
index e95e4bf..fa78165 160000 (submodule)
--- a/xvm-prodconfig
+++ b/xvm-prodconfig
@@ -1 +1 @@
-Subproject commit e95e4bf3531874145cc7e7436341cc7835f5111f
+Subproject commit fa7816564c0b631e3002e1b6a9bf4d2e82ee842a