fix memory leak (ros2#1994)

Signed-off-by: Chen Lihui <lihui.chen@sony.com>

rclcpp/src/rclcpp/parameter_map.cpp

@@ -15,6 +15,8 @@
 #include <string>
 #include <vector>
 
+#include "rcpputils/find_and_replace.hpp"
+#include "rcpputils/scope_exit.hpp"
 #include "rclcpp/parameter_map.hpp"
 
 using rclcpp::exceptions::InvalidParametersException;
@@ -132,9 +134,11 @@ rclcpp::parameter_map_from_yaml_file(const std::string & yaml_filename)
 {
   rcutils_allocator_t allocator = rcutils_get_default_allocator();
   rcl_params_t * rcl_parameters = rcl_yaml_node_struct_init(allocator);
+  RCPPUTILS_SCOPE_EXIT(rcl_yaml_node_struct_fini(rcl_parameters); );
   const char * path = yaml_filename.c_str();
   if (!rcl_parse_yaml_file(path, rcl_parameters)) {
     rclcpp::exceptions::throw_from_rcl_error(RCL_RET_ERROR);
   }
+
   return rclcpp::parameter_map_from(rcl_parameters);
 }