Internal route tables have a reduced cleanup routine

This fixes an internal table cleanup bug introduced
in ff397df7ed.

nest/route.h

@@ -164,6 +164,9 @@ typedef struct rtable {
   int pipe_busy;			/* Pipe loop detection */
   int use_count;			/* Number of protocols using this table */
   u32 rt_count;				/* Number of routes in the table */
+
+  byte internal;			/* Internal table of a protocol */
+
   struct hmap id_map;
   struct hostcache *hostcache;
   struct rtable_config *config;		/* Configuration of this table */

nest/rt-table.c

@@ -1880,6 +1880,9 @@ rt_free(resource *_r)
   DBG("Deleting routing table %s\n", r->name);
   ASSERT_DIE(r->use_count == 0);
 
+  if (r->internal)
+    return;
+
   r->config->table = NULL;
   rem_node(&r->n);
 
@@ -1931,7 +1934,7 @@ rt_setup(pool *pp, struct rtable_config *cf)
 
   fib_init(&t->fib, p, t->addr_type, sizeof(net), OFFSETOF(net, n), 0, NULL);
 
-  if (!cf->internal)
+  if (!(t->internal = cf->internal))
   {
     init_list(&t->channels);
     hmap_init(&t->id_map, p, 1024);