rib: Avoid use of orphaned ValidationPolicyConfig

Change-Id: Id1fa969a2e4b3c88a21cacdbbeda32d17834fe6f
Refs: #4759
diff --git a/rib/service.cpp b/rib/service.cpp
index c25e977..7557f2f 100644
--- a/rib/service.cpp
+++ b/rib/service.cpp
@@ -162,8 +162,8 @@
     const std::string& key = item.first;
     const ConfigSection& value = item.second;
     if (key == CFG_LOCALHOST_SECURITY || key == CFG_LOCALHOP_SECURITY) {
-      ndn::security::v2::validator_config::ValidationPolicyConfig policy;
-      policy.load(value, filename);
+      ndn::ValidatorConfig testValidator(m_face);
+      testValidator.load(value, filename);
     }
     else if (key == CFG_PREFIX_PROPAGATE) {
       // AutoPrefixPropagator does not support config dry-run