src: decouple classes from Nlsr object

refs: #1952, #2803, #3960, #4288

Change-Id: Ibe3ac3820f11e8107ee4b13e510d53c27467a6cb
diff --git a/src/update/prefix-update-processor.hpp b/src/update/prefix-update-processor.hpp
index 4491448..f397df1 100644
--- a/src/update/prefix-update-processor.hpp
+++ b/src/update/prefix-update-processor.hpp
@@ -44,7 +44,7 @@
 {
 public:
   PrefixUpdateProcessor(ndn::mgmt::Dispatcher& dispatcher,
-                        ndn::Face& face,
+                        ndn::security::ValidatorConfig& validator,
                         NamePrefixList& namePrefixList,
                         Lsdb& lsdb, const std::string& configFileName);
 
@@ -95,7 +95,7 @@
   makeAuthorization();
 
 private:
-  ndn::security::ValidatorConfig m_validator;
+  ndn::security::ValidatorConfig& m_validator;
   const std::string& m_configFileName;
 };