nua: stop further OPTIONS keepalives after one times out
nua: stop further OPTIONS keepalives after one times out

Note that we only stop after a plain keepalive probe (non-validating)
times out. When a registration probe times out, the stack can still
perform keepalives and these may get a response, because their routing
is different due to Max-Forwards: 0.

xhook/sofia-sip,xhook/sofia-sip,BelledonneCommunications/sofia-sip,xhook/sofia-sip,unispeech/sofia-sip,erdincay/sofia-sip,xhook/sofia-sip,unispeech/sofia-sip,BelledonneCommunications/sofia-sip,BelledonneCommunications/sofia-sip,BelledonneCommunications/sofia-sip,erdincay/sofia-sip,unispeech/sofia-sip,erdincay/sofia-sip,unispeech/sofia-sip,erdincay/sofia-sip,xhook/sofia-sip