Change namespace root blessing pattern

The new blessing pattern starts with dev.v.io:r instead of
dev.v.io:role.

MultiPart: 1/2
Change-Id: Id0cd3e9f3fbc7a3a65e8620dd098e6662c0c26d4
diff --git a/vmon/doc.go b/vmon/doc.go
index 9d6524e..bbd4bc4 100644
--- a/vmon/doc.go
+++ b/vmon/doc.go
@@ -49,7 +49,7 @@
    directory to use for storing security credentials
  -v23.i18n-catalogue=
    18n catalogue files to load, comma separated
- -v23.namespace.root=[/(dev.v.io:role:vprod:service:mounttabled)@ns.dev.v.io:8101]
+ -v23.namespace.root=[/(dev.v.io:r:vprod:service:mounttabled)@ns.dev.v.io:8101]
    local namespace root; can be repeated to provided multiple roots
  -v23.permissions.file=map[]
    specify a perms file as <name>:<permsfile>