Correct moribund logic about caching v2 networkstatuses

src/or/dirserv.c

@@ -1478,7 +1478,6 @@ dirserv_set_cached_networkstatus_v2(const char *networkstatus,
                                     time_t published)
 {
   cached_dir_t *d, *old_d;
-  const smartlist_t *trusted_dirs;
   if (!cached_v2_networkstatus)
     cached_v2_networkstatus = digestmap_new();
 
@@ -1501,9 +1500,9 @@ dirserv_set_cached_networkstatus_v2(const char *networkstatus,
   }
 
   /* Now purge old entries. */
-  trusted_dirs = router_get_trusted_dir_servers();
+
   if (digestmap_size(cached_v2_networkstatus) >
-      smartlist_len(trusted_dirs) + MAX_UNTRUSTED_NETWORKSTATUSES) {
+      get_n_authorities(V2_DIRINFO) + MAX_UNTRUSTED_NETWORKSTATUSES) {
     /* We need to remove the oldest untrusted networkstatus. */
     const char *oldest = NULL;
     time_t oldest_published = TIME_MAX;