hostname value defaults to "35c12eb4-ws-discovery" not system hostname

First, thanks for creating this add-on. It works well and I can finally see my HA samba shares in Windows' network browser.

I noted that if hostname is left blank in the configuration, what is advertised isn't the system hostname (as stated in the documentation) but instead it's the add-on hostname "35c12eb4-ws-discovery". Perhaps that can be fixed or otherwise update the documentation.