xl: CreateFile shouldn't prematurely timeout (#11878)

For large objects taking more than '3 minutes' response
times in a single PUT operation can timeout prematurely
as 'ResponseHeader' timeout hits for 3 minutes. Avoid
this by keeping the connection active during CreateFile
phase.

cmd/storage-rest-client.go

@@ -337,7 +337,12 @@ func (client *storageRESTClient) CreateFile(ctx context.Context, volume, path st
 	values.Set(storageRESTFilePath, path)
 	values.Set(storageRESTLength, strconv.Itoa(int(size)))
 	respBody, err := client.call(ctx, storageRESTMethodCreateFile, values, ioutil.NopCloser(reader), size)
-	defer http.DrainBody(respBody)
+	if err != nil {
+		return err
+	}
+	waitReader, err := waitForHTTPResponse(respBody)
+	defer http.DrainBody(ioutil.NopCloser(waitReader))
+	defer respBody.Close()
 	return err
 }