return xml encoded NotFound status code for s3 delete

weed/s3api/s3api_object_handlers.go

@@ -112,6 +112,10 @@ func (s3a *S3ApiServer) DeleteObjectHandler(w http.ResponseWriter, r *http.Reque
 		for k, v := range proxyResponse.Header {
 			w.Header()[k] = v
 		}
+		if proxyResponse.StatusCode == http.StatusNotFound {
+			writeErrorResponse(w, ErrNoSuchKey, r.URL)
+			return
+		}
 		w.WriteHeader(proxyResponse.StatusCode)
 	})