Fix discovery of minidlna in VLC for Linux

Some time ago I installed minidlna to serve my contents in my home lan. Even though VLC installed on my phone always discoved the minidlna server, VLC on my Linux machine didn’t do it: it often couldn’t discover it. The problem was the configuration of the notification interval of minidlna and the solution was to decrease this value: # SSDP notify interval, in seconds. notify_interval=20