Fixed handling end errors in Session.end

Ignore-this: 7c0ef252807c7a1f2ff59b525f915ec7

darcs-hash:20090910120223-1e3d8-cd997edfcc512eb69fec9bf2a750310e93fd3f2f
Cleaned-up sipsimple.clients.log

Ignore-this: 2b5bab89eea988bfa3d19a65a4456f1

darcs-hash:20090911122327-1e3d8-0ab59f5dfa9e4aabfa4d725cc7e3d5d9cfb8cf79