use SIPSimpleSetting.local_ip.value in session

darcs-hash:20090320154343-58103-c447c12bffbb55875061ec972b4839795b765ed3
Prevent possible race condition in Session.reject()

darcs-hash:20090320180953-58103-f6120b8bd8ebdef724818c024958f9e785f6d6a5