Return an error in mqtt3_db_client_insert() and m_d_c_update() if will is enabled but either will_topic or will_message is NULL.
Return an error in mqtt3_db_client_insert() and m_d_c_update() if will is enabled but either will_topic or will_message is NULL.

tempbottle/mosquitto,tempbottle/mosquitto,tempbottle/mosquitto,tempbottle/mosquitto,tempbottle/mosquitto