fix warnings

Change-Id: I23aa29d8cb2ddc77d86aee14c5e99f6c3945029b
diff --git a/tests/unit-tests/challenge-email.t.cpp b/tests/unit-tests/challenge-email.t.cpp
index 5801bca..426ea03 100644
--- a/tests/unit-tests/challenge-email.t.cpp
+++ b/tests/unit-tests/challenge-email.t.cpp
@@ -45,7 +45,7 @@
   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));
 
@@ -96,7 +96,7 @@
   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));
 
@@ -119,7 +119,7 @@
   auto cert = key.getDefaultCertificate();
   JsonSection json;
   json.put(ChallengeEmail::PARAMETER_KEY_CODE, "4567");
-  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,
                            "email", ChallengeEmail::NEED_CODE, time::system_clock::now(),
@@ -143,7 +143,7 @@
   auto cert = key.getDefaultCertificate();
   JsonSection json;
   json.put(ChallengeEmail::PARAMETER_KEY_CODE, "4567");
-  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,
                            "email", ChallengeEmail::NEED_CODE, time::system_clock::now(),