small changes in log_manager.cpp and add is_database_primitive type traits and test

source/core/logger/log_manager.cpp

@@ -36,6 +36,7 @@ void log_manager::clear_all_sinks(const std::string &domain_name) {
 void log_manager::clear() {
   std::lock_guard lock(mutex_);
   log_domain_map_.clear();
+  default_log_domain_->clear();
 }
 
 void log_manager::max_default_log_level(const log_level max_level) {