security: Allow reloading ValidationPolicyConfig / ValidatorConfig

Change-Id: Idba53c0b4e2cf645d3d0e6c76c57a1b54995462a
Refs: #4261
diff --git a/src/security/v2/certificate-cache.hpp b/src/security/v2/certificate-cache.hpp
index f649776..a5109a8 100644
--- a/src/security/v2/certificate-cache.hpp
+++ b/src/security/v2/certificate-cache.hpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2013-2017 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
@@ -63,6 +63,12 @@
   insert(const Certificate& cert);
 
   /**
+   * @brief Remove all certificates from cache
+   */
+  void
+  clear();
+
+  /**
    * @brief Get certificate given key name
    * @param certPrefix  Certificate prefix for searching the certificate.
    * @return The found certificate, nullptr if not found.