security+tests: Fix small bugs with uninitialized and leaked memory

Change-Id: I525ac8d284783ffff08e31dc7fe2a892bfc78307
diff --git a/src/security/command-interest-signer.hpp b/src/security/command-interest-signer.hpp
index 7033b3f..6c5e2ce 100644
--- a/src/security/command-interest-signer.hpp
+++ b/src/security/command-interest-signer.hpp
@@ -41,6 +41,8 @@
 class CommandInterestPreparer : noncopyable
 {
 public:
+  CommandInterestPreparer();
+
   /**
    * @brief Prepare name of the CommandInterest
    *