Fix for case of weird devices sending weird things

[fireduck64]

Situation:

Local network has pfSense router with upnp enabled, also has Ubiquity Cloudkey 2.0 that feels like putting its oar in.

A reply comes in to the discovery from the cloud key:

HTTP/1.1 200 OK
Cache-Control: max-age = 60
Ext:
Location: http://10.3.0.75:8080/upnp
SERVER: UPnP/1.0 UniFi/6.5.55
ST: upnp:rootdevice
USN: uuid:3C86D905-39E4-4FDC-963C-04E19F2791BB::upnp:rootdevice

This results in:
java.io.FileNotFoundException: http://10.3.0.75:8080/upnp
(Apparently the URL they provide results in a 404)

After this, the proper router reply comes in. This change is to basically ignore any device where we get errors trying to parse or understand them.