[cleanup] Make command nodes static

The cmd_nodes used to configure vty, can mostly be static so
(basic data hiding 101).
diff --git a/lib/routemap.c b/lib/routemap.c
index 58ed09a..5f7a318 100644
--- a/lib/routemap.c
+++ b/lib/routemap.c
@@ -1280,7 +1280,7 @@
 }
 
 /* Route map node structure. */
-struct cmd_node rmap_node =
+static struct cmd_node rmap_node =
 {
   RMAP_NODE,
   "%s(config-route-map)# ",