{dis,en}abling DirCache is a semantic change

src/or/routerlist.c

@@ -4904,7 +4904,8 @@ router_differences_are_cosmetic(const routerinfo_t *r1, const routerinfo_t *r2)
       (r1->contact_info && r2->contact_info &&
        strcasecmp(r1->contact_info, r2->contact_info)) ||
       r1->is_hibernating != r2->is_hibernating ||
-      cmp_addr_policies(r1->exit_policy, r2->exit_policy))
+      cmp_addr_policies(r1->exit_policy, r2->exit_policy) ||
+      r1->dir_cache != r2->dir_cache)
     return 0;
   if ((r1->declared_family == NULL) != (r2->declared_family == NULL))
     return 0;