Update the startup config

        :param startup_config: content of the startup configuration file

def startup_config_content(self, startup_config):
        """
        Update the startup config

        :param startup_config: content of the startup configuration file
        """

        try:
            startup_config_path = os.path.join(self.working_dir, "startup-config.cfg")

            if startup_config is None:
                startup_config = ''

            # We disallow erasing the startup config file
            if len(startup_config) == 0 and os.path.exists(startup_config_path):
                return

            with open(startup_config_path, 'w+', encoding='utf-8') as f:
                if len(startup_config) == 0:
                    f.write('')
                else:
                    startup_config = startup_config.replace("%h", self._name)
                    f.write(startup_config)

            vlan_file = os.path.join(self.working_dir, "vlan.dat-{:05d}".format(self.application_id))
            if os.path.exists(vlan_file):
                try:
                    os.remove(vlan_file)
                except OSError as e:
                    log.error("Could not delete VLAN file '{}': {}".format(vlan_file, e))

        except OSError as e:
            raise IOUError("Can't write startup-config file '{}': {}".format(startup_config_path, e))