Remove old stuff from the AgentCallbackLogin days and only autocomplete agents...

Remove old stuff from the AgentCallbackLogin days and only autocomplete agents in the agent logoff CLI command that are logged in. (issue #9952 reported by eliel)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@68900 65c4cc65-6c06-0410-ace0-fbb531ad65f3