Fix mistake in ObjectRepository::Create

Objects that could not be loaded were being returned with a success status causing blanks in the index file.

src/openrct2/object/ObjectRepository.cpp

@@ -111,7 +111,7 @@ public:
         }
         else
         {
-            return std::make_tuple(true, ObjectRepositoryItem());
+            return std::make_tuple(false, ObjectRepositoryItem());
         }
     }