small correction to the dataset creation methods

src/DataSet.cpp

@@ -113,6 +113,7 @@ DataSet DataSet::createDataSet(const std::string& name) {
         throw Exception("Invalid character '/' in dataset name");
     }
     m_impl->m_datastore->store(m_impl->m_level+1, fullname(), name, std::vector<char>());
+    return DataSet(*(m_impl->m_datastore), 1, fullname(), name);
 }
 
 }

src/DataStore.cpp

@@ -338,7 +338,7 @@ DataSet DataStore::createDataSet(const std::string& name) {
         throw Exception("Invalid character '/' in dataset name");
     }
     store(1, "", name, std::vector<char>());
-    return DataSet(*this, 1, name);
+    return DataSet(*this, 1, "", name);
 }
 
 bool DataStore::load(uint8_t level, const std::string& containerName,