Stay listening on CTRL+D while in a call in sip_audio_session.py

darcs-hash:20090417140957-58103-83319d93bff16546488afcd865c7a59c86a9ed72
Fix for last sip_audio_session.py patch

darcs-hash:20090417145332-58103-5d2f0a170adaa742914e78f9ad8b5e066d323c79