fix warnings

Change-Id: I23aa29d8cb2ddc77d86aee14c5e99f6c3945029b
diff --git a/tests/unit-tests/challenge-pin.t.cpp b/tests/unit-tests/challenge-pin.t.cpp
index f790bad..4b87a1e 100644
--- a/tests/unit-tests/challenge-pin.t.cpp
+++ b/tests/unit-tests/challenge-pin.t.cpp
@@ -38,7 +38,7 @@
   auto identity = addIdentity(Name("/ndn/site1"));
   auto key = identity.getDefaultKey();
   auto cert = key.getDefaultCertificate();
-  RequestId requestId = {1, 2, 3, 4, 5, 6, 7, 8};
+  RequestId requestId = {{1,2,3,4,5,6,7,8}};
   std::array<uint8_t, 16> aesKey;
   ca::RequestState request(Name("/ndn/site1"), requestId, RequestType::NEW, Status::BEFORE_CHALLENGE, cert, std::move(aesKey));
 
@@ -57,7 +57,7 @@
   auto cert = key.getDefaultCertificate();
   JsonSection secret;
   secret.add(ChallengePin::PARAMETER_KEY_CODE, "12345");
-  RequestId requestId = {1, 2, 3, 4, 5, 6, 7, 8};
+  RequestId requestId = {{1,2,3,4,5,6,7,8}};
   std::array<uint8_t, 16> aesKey;
   ca::RequestState request(Name("/ndn/site1"), requestId, RequestType::NEW, Status::CHALLENGE, cert,
                            "pin", ChallengePin::NEED_CODE, time::system_clock::now(),
@@ -81,7 +81,7 @@
   auto cert = key.getDefaultCertificate();
   JsonSection secret;
   secret.add(ChallengePin::PARAMETER_KEY_CODE, "12345");
-  RequestId requestId = {1, 2, 3, 4, 5, 6, 7, 8};
+  RequestId requestId = {{1,2,3,4,5,6,7,8}};
   std::array<uint8_t, 16> aesKey;
   ca::RequestState request(Name("/ndn/site1"), requestId, RequestType::NEW, Status::CHALLENGE, cert,
                            "pin", ChallengePin::NEED_CODE, time::system_clock::now(),