nlsr: Don't use ndn aliases provided by ndn-cxx/common.hpp

refs: #3983

Change-Id: I31da8d68e0285dcfe9c7d3e5e678c00397d22bef
diff --git a/tests/security/test-certificate-store.cpp b/tests/security/test-certificate-store.cpp
index 42964eb..de3207e 100644
--- a/tests/security/test-certificate-store.cpp
+++ b/tests/security/test-certificate-store.cpp
@@ -51,7 +51,7 @@
   }
 
 public:
-  shared_ptr<ndn::IdentityCertificate> certificate;
+  std::shared_ptr<ndn::IdentityCertificate> certificate;
   ndn::Name certificateKey;
 };