Fixed DNSLookup.lookup_service to report failure for no results

Ignore-this: 75737c715679e24a4c1be36aaeb4d2d7

darcs-hash:20090618121323-1e3d8-76dba9a66c091627402ccb76257c323397278e3a
Fixed display of remote identity in sip_session scripts

Ignore-this: 38d8e8b0bb2c38f580dd309e7bd36d30

darcs-hash:20090618163341-1e3d8-fe657bf70e35e12f5ae7c52b6e200bf9d38d2c03