when the flag isn't set we'd set the text to urlStr, urlStr however
was the original string *with* the port. since we want the port stripped
we need to actually set url.url() otherwise the KCM loading its own
settings would result in
Proxy: [socks://localhost:1080] Port: [1080]
which when written back to the file would result in broken data as we
do not sanitize the proxy url text WRT port when saving