Update default compilation flags

Synced from ndn-tools

Change-Id: I95e451f6978f473ad6f616277803464effffd3a7
diff --git a/src/ca-storage.cpp b/src/ca-storage.cpp
index 3f8aeb5..ebe5c98 100644
--- a/src/ca-storage.cpp
+++ b/src/ca-storage.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2017, Regents of the University of California.
+ * Copyright (c) 2017-2018, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,6 +23,8 @@
 namespace ndn {
 namespace ndncert {
 
+CaStorage::~CaStorage() = default;
+
 unique_ptr<CaStorage>
 CaStorage::createCaStorage(const std::string& caStorageType)
 {