util: Deprecate CommandInterestGenerator and CommandInterestValidator

Change-Id: Ib56f06702c571037990bf9e3ed1e0b973697f0f3
Refs: #1696
diff --git a/src/util/command-interest-generator.hpp b/src/util/command-interest-generator.hpp
index 8f97b7b..651a19b 100644
--- a/src/util/command-interest-generator.hpp
+++ b/src/util/command-interest-generator.hpp
@@ -32,6 +32,9 @@
 /**
  * @brief Helper class to generate CommandInterests
  *
+ * @deprecated Use SignedInterest (generated by KeyChain) instead.
+ * See KeyChain::sign and KeyChain::signByIdentity methods.
+ *
  * @see http://redmine.named-data.net/projects/nfd/wiki/Command_Interests
  */
 class CommandInterestGenerator