Update Azure SDK (#4985)

vendor/github.com/Azure/go-autorest/autorest/retriablerequest.go

@@ -0,0 +1,38 @@
+package autorest
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+	"net/http"
+)
+
+// NewRetriableRequest returns a wrapper around an HTTP request that support retry logic.
+func NewRetriableRequest(req *http.Request) *RetriableRequest {
+	return &RetriableRequest{req: req}
+}
+
+// Request returns the wrapped HTTP request.
+func (rr *RetriableRequest) Request() *http.Request {
+	return rr.req
+}
+
+func (rr *RetriableRequest) prepareFromByteReader() (err error) {
+	// fall back to making a copy (only do this once)
+	b := []byte{}
+	if rr.req.ContentLength > 0 {
+		b = make([]byte, rr.req.ContentLength)
+		_, err = io.ReadFull(rr.req.Body, b)
+		if err != nil {
+			return err
+		}
+	} else {
+		b, err = ioutil.ReadAll(rr.req.Body)
+		if err != nil {
+			return err
+		}
+	}
+	rr.br = bytes.NewReader(b)
+	rr.req.Body = ioutil.NopCloser(rr.br)
+	return err
+}