Avoid deprecated ndnsec commands

Change-Id: I1724bfe8aa09ee2141d6cedb30ea23caaa080c5b
diff --git a/ndn-tools/debian/ndnping.postinst b/ndn-tools/debian/ndnping.postinst
index 8b04456..f376cb0 100644
--- a/ndn-tools/debian/ndnping.postinst
+++ b/ndn-tools/debian/ndnping.postinst
@@ -10,8 +10,8 @@
     # Create HOME and generate self-signed NDN certificate
     sudo mkdir -p /var/lib/ndn/$APP/.ndn
     sudo chown -R ndn:ndn /var/lib/ndn/$APP
-    sudo -u ndn -g ndn HOME=/var/lib/ndn/$APP ndnsec-keygen /localhost/daemons/$APP | \
-      sudo -u ndn -g ndn HOME=/var/lib/ndn/$APP ndnsec-install-cert -
+    sudo -u ndn -g ndn HOME=/var/lib/ndn/$APP ndnsec key-gen /localhost/daemons/$APP | \
+      sudo -u ndn -g ndn HOME=/var/lib/ndn/$APP ndnsec cert-install -
 fi
 
 #DEBHELPER#