call.py: make ^C clean up connection in incoming mode.
call.py: make ^C clean up connection in incoming mode.

Previously, after you'd received a call self.channel was non-None when
KeyboardInterrupt occurred, so Close() would be called on it. But the
channel had gone away, so Close() would throw an (unhandled) exception,
so call.py would never get around to calling Disconnect().

PabloCastellano/telepathy-python,epage/telepathy-python,freedesktop-unofficial-mirror/telepathy__telepathy-python,PabloCastellano/telepathy-python,detrout/telepathy-python,max-posedon/telepathy-python,detrout/telepathy-python,max-posedon/telepathy-python,freedesktop-unofficial-mirror/telepathy__telepathy-python,epage/telepathy-python