This change ensures that the INVITE session remains valid for the lifetime
of the session object itself by increasing the session count on the dialog that
the INVITE session is allocated from. Once this reaches zero (normally as a result
of decrementing it within the session destructor) the dialog, and INVITE session,
are destroyed.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@389609 65c4cc65-6c06-0410-ace0-fbb531ad65f3