[ledger] Avoid creating Objects directly.

This change makes the test for inspect use the ObjectDir::Make method
instead of directly creating shared pointers. This is necessary for the
migration to use std::shared_ptr in garnet.

TEST=runtests

Change-Id: I71062fb3ddbd52707d7e362ea8ca06f1dfd3f626
diff --git a/bin/ledger/app/ledger_repository_factory_impl_unittest.cc b/bin/ledger/app/ledger_repository_factory_impl_unittest.cc
index 5391029..4ef4e5f 100644
--- a/bin/ledger/app/ledger_repository_factory_impl_unittest.cc
+++ b/bin/ledger/app/ledger_repository_factory_impl_unittest.cc
@@ -34,8 +34,7 @@
 class LedgerRepositoryFactoryImplTest : public TestWithEnvironment {
  public:
   LedgerRepositoryFactoryImplTest() {
-    object_dir_ = component::ObjectDir(
-        fbl::MakeRefCounted<component::Object>(kObjectsName));
+    object_dir_ = component::ObjectDir::Make({kObjectsName.data(), kObjectsName.size()});
     repository_factory_ = std::make_unique<LedgerRepositoryFactoryImpl>(
         &environment_, nullptr, object_dir_);
   }