Re-think integration vendoring

- remove docker/docker from  Traefik vendor (unused)
- use `ignore` for all Traefik vendor in integration glide.
- defined only integration specific version of the dependencies.

integration/vendor/github.com/Sirupsen/logrus/writer.go

@@ -7,40 +7,18 @@ import (
 )
 
 func (logger *Logger) Writer() *io.PipeWriter {
-	return logger.WriterLevel(InfoLevel)
-}
-
-func (logger *Logger) WriterLevel(level Level) *io.PipeWriter {
 	reader, writer := io.Pipe()
 
-	var printFunc func(args ...interface{})
-	switch level {
-	case DebugLevel:
-		printFunc = logger.Debug
-	case InfoLevel:
-		printFunc = logger.Info
-	case WarnLevel:
-		printFunc = logger.Warn
-	case ErrorLevel:
-		printFunc = logger.Error
-	case FatalLevel:
-		printFunc = logger.Fatal
-	case PanicLevel:
-		printFunc = logger.Panic
-	default:
-		printFunc = logger.Print
-	}
-
-	go logger.writerScanner(reader, printFunc)
+	go logger.writerScanner(reader)
 	runtime.SetFinalizer(writer, writerFinalizer)
 
 	return writer
 }
 
-func (logger *Logger) writerScanner(reader *io.PipeReader, printFunc func(args ...interface{})) {
+func (logger *Logger) writerScanner(reader *io.PipeReader) {
 	scanner := bufio.NewScanner(reader)
 	for scanner.Scan() {
-		printFunc(scanner.Text())
+		logger.Print(scanner.Text())
 	}
 	if err := scanner.Err(); err != nil {
 		logger.Errorf("Error while reading from Writer: %s", err)