Fixed outgoing call remote User-Agent detection in sip_audio_session.py

darcs-hash:20081203193203-58103-6a97b25c16201390801c4a469f92abfd2bfcf21f
Fixed detection of situation where SDP negotiation is done, but the session got disconnected

darcs-hash:20081203193243-58103-ae9d9f7d967b626fa49dc1e59e718dc0eaa67c68