simplify client new/revoke

Change-Id: Ieffad88163393ec6f5a1e04e200df524dbf2c447
diff --git a/tools/ndncert-client.cpp b/tools/ndncert-client.cpp
index 096ceb2..2266a25 100644
--- a/tools/ndncert-client.cpp
+++ b/tools/ndncert-client.cpp
@@ -146,7 +146,7 @@
 newCb(const Data& reply)
 {
   int challengeIndex = 0;
-  auto challengeList = client.onNewResponse(reply);
+  auto challengeList = client.onNewRenewRevokeResponse(reply);
   if (challengeList.size() < 1) {
     std::cerr << "There is no available challenge provided by the CA. Exit" << std::endl;
     return;