(fix #543)added body to error when Post encounter 4xx response
(fix #543)added body to error when Post encounter 4xx response
chrislusf/seaweedfs,chrislusf/seaweedfs,chrislusf/seaweedfs,k85169336/seaweedfs,k85169336/seaweedfs,hxiaodon/seaweedfs,chrislusf/seaweedfs,hxiaodon/seaweedfs