build: Add warning for non-virtual destructor and fix discovered issues

Change-Id: I1d67b9b63d84d8524580e80ac06c3efef860c56a
diff --git a/tests/tools/mock-nfd-mgmt-fixture.hpp b/tests/tools/mock-nfd-mgmt-fixture.hpp
index 4eeab41..d0498e5 100644
--- a/tests/tools/mock-nfd-mgmt-fixture.hpp
+++ b/tests/tools/mock-nfd-mgmt-fixture.hpp
@@ -26,11 +26,11 @@
 #ifndef NFD_TESTS_TOOLS_MOCK_NFD_MGMT_FIXTURE_HPP
 #define NFD_TESTS_TOOLS_MOCK_NFD_MGMT_FIXTURE_HPP
 
-#include <ndn-cxx/util/dummy-client-face.hpp>
-
 #include "tests/test-common.hpp"
 #include "tests/identity-management-fixture.hpp"
 
+#include <ndn-cxx/util/dummy-client-face.hpp>
+
 namespace nfd {
 namespace tools {
 namespace tests {
@@ -56,6 +56,9 @@
     });
   }
 
+  virtual
+  ~MockNfdMgmtFixture() = default;
+
 protected: // ControlCommand
   /** \brief check the Interest is a command with specified prefix
    *  \retval nullopt last Interest is not the expected command