mgmt: rename extractRequester() and support signed Interest v0.3

Change-Id: I6bb6635896fa1b9fa54beb70b902c5a35831dc9c
diff --git a/daemon/mgmt/rib-manager.cpp b/daemon/mgmt/rib-manager.cpp
index afeca1c..484b4eb 100644
--- a/daemon/mgmt/rib-manager.cpp
+++ b/daemon/mgmt/rib-manager.cpp
@@ -313,7 +313,7 @@
 
     auto& validator = prefix == LOCALHOST_TOP_PREFIX ? m_localhostValidator : m_localhopValidator;
     validator.validate(interest,
-                       [&interest, accept] (auto&&...) { extractRequester(interest, accept); },
+                       [&interest, accept] (auto&&...) { accept(extractSigner(interest)); },
                        [reject] (auto&&...) { reject(ndn::mgmt::RejectReply::STATUS403); });
   };
 }