fix: mem为0时内存不设限

pluginmgr/plugin_proc_mgr.go

@@ -124,7 +124,7 @@ func (mgr *PluginProcessMgr) detection() {
 		l.Infof("plugin process %s memory rss: %d", conf.Name, rss)
 
 		// 插件进程内存rss达到限制，重启
-		if rss > conf.Mem {
+		if conf.Mem != 0 && rss > conf.Mem {
 			l.Warn("plugin process %s memory rss(%d) reach limit(%d), restart", conf.Name, rss, conf.Mem)
 			p.shutdown()
 			mgr.registerProcess(conf)