delete references to ndn-cxx KeyChain v1

This commit also fixes an assertation error in TestClientModule/ProbeAndNew
test case when running with a debug build of ndn-cxx.

refs #4089

Change-Id: Ie1f6236e679f1bb9e7f269280bc3de78c2fe30f1
diff --git a/src/challenge-module.cpp b/src/challenge-module.cpp
index 371be25..224a30c 100644
--- a/src/challenge-module.cpp
+++ b/src/challenge-module.cpp
@@ -20,7 +20,7 @@
 
 #include "challenge-module.hpp"
 #include "logging.hpp"
-#include <random>
+#include <ndn-cxx/util/random.hpp>
 
 namespace ndn {
 namespace ndncert {