fix umgmt ListenAndServe to wait for the shutdown callbacks to execute
fix umgmt ListenAndServe to wait for the shutdown callbacks to execute

fanngyuan/vitess,fanngyuan/vitess,fanngyuan/vitess,nso95/vitess,nso95/vitess,nso95/vitess,fanngyuan/vitess,fanngyuan/vitess,nso95/vitess,nso95/vitess