security: Change in KeyChain creation API

Also, enabling creation of default public/private storages

Change-Id: I77e83b4a7f7e043dce372145d80366b7bc2eb3e0
diff --git a/include/ndn-cpp/security/identity/identity-manager.hpp b/include/ndn-cpp/security/identity/identity-manager.hpp
index 5ed7771..e1c11df 100644
--- a/include/ndn-cpp/security/identity/identity-manager.hpp
+++ b/include/ndn-cpp/security/identity/identity-manager.hpp
@@ -14,11 +14,10 @@
 #include "../certificate/public-key.hpp"
 
 #include "../../data.hpp"
+#include "../certificate/identity-certificate.hpp"
 
 namespace ndn {
 
-class IdentityCertificate;
-
 /**
  * An IdentityManager is the interface of operations related to identity, keys, and certificates.
  */
@@ -26,8 +25,8 @@
 public:
   struct Error : public std::runtime_error { Error(const std::string &what) : std::runtime_error(what) {} };
 
-  IdentityManager(const ptr_lib::shared_ptr<IdentityStorage>   &identityStorage   = DefaultIdentityStorage,
-                  const ptr_lib::shared_ptr<PrivateKeyStorage> &privateKeyStorage = DefaultPrivateKeyStorage);
+  IdentityManager(const ptr_lib::shared_ptr<IdentityStorage>   &identityStorage,
+                  const ptr_lib::shared_ptr<PrivateKeyStorage> &privateKeyStorage);
 
   inline IdentityStorage&
   info();
@@ -261,10 +260,6 @@
   void
   selfSign (IdentityCertificate& cert);
 
-public:
-  static const ptr_lib::shared_ptr<IdentityStorage>   DefaultIdentityStorage;
-  static const ptr_lib::shared_ptr<PrivateKeyStorage> DefaultPrivateKeyStorage;
-
 private:
   /**
    * Generate a key pair for the specified identity.