Fix logging in rmw_node_info_and_types.cpp (#273)

When logging a rcutils_error_string_t variable, the
str field of the rcutils_error_string_t variable needs
to be logged, not the struct directly.

Signed-off-by: Thomas Moulard <tmoulard@amazon.com>

rmw_fastrtps_shared_cpp/src/rmw_node_info_and_types.cpp

@@ -206,7 +206,7 @@ __copy_data_to_results(
  if (rmw_ret != RMW_RET_OK) {
  RCUTILS_LOG_ERROR_NAMED(
  kLoggerTag,
- "error during report of error: %s", rmw_get_error_string());
+ "error during report of error: %s", rmw_get_error_string().str);
  }
  };
  // Setup demangling functions based on no_demangle option
@@ -444,7 +444,7 @@ __rmw_get_service_names_and_types_by_node(
  if (rmw_ret != RMW_RET_OK) {
  RCUTILS_LOG_ERROR_NAMED(
  kLoggerTag,
- "error during report of error: %s", rmw_get_error_string());
+ "error during report of error: %s", rmw_get_error_string().str);
  }
  };
  // For each service, store the name, initialize the string array for types, and store all types