remove task member in dns.Server.
remove task member in dns.Server.

panzer13/v2ray-core,panzer13/v2ray-core,v2ray/v2ray-core,simpleman1984/v2ray-core,v2ray/v2ray-core,simpleman1984/v2ray-core,LiuWenJu/v2ray-core,LiuWenJu/v2ray-core,simpleman1984/v2ray-core