Put sip history stuff in (for real) and provide voicemail context (when not...

Put sip history stuff in (for real) and provide voicemail context (when not default) in some critical places (bug #1609)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@2950 65c4cc65-6c06-0410-ace0-fbb531ad65f3