@Override
	public void update(String ip, String name) {
		AgentInfo agentInfo = getAgent(ip, name);
		if (agentInfo == null) {
			return;
		}
		publishTopic(agentInfo, UPDATE_AGENT);
	}
Stop agent. If it's in cluster mode, it queue to agentRequestCache.
otherwise, it send stop message to the agent.

@param ip ip of agent to stop.
@param name host name of agent to stop.
ngrinder-controller/src/main/java/org/ngrinder/agent/service/AgentService.java