sip_session2: minor internal change

darcs-hash:20090424085939-b2873-c5abd87b0a328e139ca1b69a1984193e497bce1c
sip_session2: change the prompt to the new session right after the user pressed Y, not later when it actually connected

darcs-hash:20090424090005-b2873-bbd661565407acdf499a50e39f3185dab5b1c4bb