fix service stop on OSX to not kill Agent.Listener
fix service stop on OSX to not kill Agent.Listener

vithati/vsts-agent,vithati/vsts-agent,vithati/vsts-agent,lkillgore/vsts-agent,kasubram/vsts-agent,Microsoft/vsts-agent,Microsoft/vsts-agent,kasubram/vsts-agent,lkillgore/vsts-agent,kasubram/vsts-agent,Microsoft/vsts-agent,lkillgore/vsts-agent,lkillgore/vsts-agent,kasubram/vsts-agent,Microsoft/vsts-agent