daemon: print exception errors when failing to parse config file

When an exception happens while reading the config file, we need
to print the error, as the logging system isn't initialized yet,
so the generic catch will not print anything.

src/daemon/main.cpp

@@ -180,7 +180,16 @@ int main(int argc, char const * argv[])
     boost::system::error_code ec;
     if (bf::exists(config_path, ec))
     {
-      po::store(po::parse_config_file<char>(config_path.string<std::string>().c_str(), core_settings), vm);
+      try
+      {
+        po::store(po::parse_config_file<char>(config_path.string<std::string>().c_str(), core_settings), vm);
+      }
+      catch (const std::exception &e)
+      {
+        // log system isn't initialized yet
+        std::cerr << "Error parsing config file: " << e.what() << std::endl;
+        throw;
+      }
     }
     po::notify(vm);