mgmt: respond Nack when query is invalid

refs #1993

Change-Id: I21e398cd7b2e562b7dc759a89f6e668960e72c41
diff --git a/daemon/mgmt/manager-base.hpp b/daemon/mgmt/manager-base.hpp
index feaa54a..1611615 100644
--- a/daemon/mgmt/manager-base.hpp
+++ b/daemon/mgmt/manager-base.hpp
@@ -94,8 +94,8 @@
                const std::string& text,
                const Block& body);
 
-  //void
-  //sendNack(const Name& name);
+  void
+  sendNack(const Name& name);
 
   virtual bool
   validateParameters(const ControlCommand& command,