add namespace for requester

Change-Id: I3de037dffd702edff9f87a87e8e684161db3d329
diff --git a/src/requester.hpp b/src/requester.hpp
index cb3d10d..fddd35b 100644
--- a/src/requester.hpp
+++ b/src/requester.hpp
@@ -25,10 +25,7 @@
 
 namespace ndn {
 namespace ndncert {
-
-// TODO
-// For each RequesterState, create a validator instance and initialize it with CA's cert
-// The validator instance should be in CaProfile
+namespace requester {
 
 class Requester : noncopyable
 {
@@ -206,6 +203,7 @@
   processIfError(const Data& data);
 };
 
+} // namespace requester
 } // namespace ndncert
 } // namespace ndn