update gobgp pkg

vendor/github.com/sirupsen/logrus/writer.go

@@ -6,10 +6,16 @@ import (
 	"runtime"
 )
 
+// Writer at INFO level. See WriterLevel for details.
 func (logger *Logger) Writer() *io.PipeWriter {
 	return logger.WriterLevel(InfoLevel)
 }
 
+// WriterLevel returns an io.Writer that can be used to write arbitrary text to
+// the logger at the given log level. Each line written to the writer will be
+// printed in the usual way using formatters and hooks. The writer is part of an
+// io.Pipe and it is the callers responsibility to close the writer when done.
+// This can be used to override the standard library logger easily.
 func (logger *Logger) WriterLevel(level Level) *io.PipeWriter {
 	return NewEntry(logger).WriterLevel(level)
 }
@@ -24,6 +30,8 @@ func (entry *Entry) WriterLevel(level Level) *io.PipeWriter {
 	var printFunc func(args ...interface{})
 
 	switch level {
+	case TraceLevel:
+		printFunc = entry.Trace
 	case DebugLevel:
 		printFunc = entry.Debug
 	case InfoLevel: