security: provide getKeyLocatorName helper function

refs #3920

Change-Id: Iba8fa7776ca63445608f4eb6fa2e4c54307cc99f
diff --git a/src/security/v2/validation-state.hpp b/src/security/v2/validation-state.hpp
index 821b85c..8d0e5ba 100644
--- a/src/security/v2/validation-state.hpp
+++ b/src/security/v2/validation-state.hpp
@@ -27,8 +27,9 @@
 #include "certificate.hpp"
 #include "../../util/signal.hpp"
 
-#include <unordered_set>
 #include <list>
+#include <unordered_set>
+#include <boost/logic/tribool.hpp>
 
 namespace ndn {
 namespace security {
@@ -65,6 +66,12 @@
   virtual
   ~ValidationState();
 
+  boost::logic::tribool
+  getOutcome() const
+  {
+    return m_outcome;
+  }
+
   /**
    * @brief Call the failure callback
    */
@@ -129,7 +136,7 @@
   verifyCertificateChain(const Certificate& trustedCert);
 
 protected:
-  bool m_hasOutcome;
+  boost::logic::tribool m_outcome;
 
 private:
   std::unordered_set<Name> m_seenCertificateNames;