[wrt] Fix SSDP multicast join/rejoin happening too frequently
[wrt] Fix SSDP multicast join/rejoin happening too frequently

CapnBry/HeaterMeter,CapnBry/HeaterMeter,CapnBry/HeaterMeter,shmick/HeaterMeter,shmick/HeaterMeter,shmick/HeaterMeter,CapnBry/HeaterMeter,shmick/HeaterMeter,shmick/HeaterMeter,CapnBry/HeaterMeter,CapnBry/HeaterMeter,CapnBry/HeaterMeter,shmick/HeaterMeter,shmick/HeaterMeter