security: Fix typo in osx-private-key-storage. Need // comment in #endif.
diff --git a/ndn-cpp/security/identity/osx-private-key-storage.cpp b/ndn-cpp/security/identity/osx-private-key-storage.cpp
index 5728ad7..136d054 100644
--- a/ndn-cpp/security/identity/osx-private-key-storage.cpp
+++ b/ndn-cpp/security/identity/osx-private-key-storage.cpp
@@ -512,4 +512,4 @@
   
 }
 
-#endif NDN_CPP_HAVE_OSX_SECURITY
+#endif // NDN_CPP_HAVE_OSX_SECURITY