gosrc: Setup GitHub authentication for print command

Change-Id: I5834dbe015954b6034bfc9e2e46928f8d8da393f
Reviewed-on: https://go-review.googlesource.com/43498
Reviewed-by: Sarah Adams <shadams@google.com>
diff --git a/gosrc/print.go b/gosrc/print.go
index f833bc3..260592a 100644
--- a/gosrc/print.go
+++ b/gosrc/print.go
@@ -19,6 +19,7 @@
 	"strings"
 
 	"github.com/golang/gddo/gosrc"
+	"github.com/golang/gddo/httputil"
 )
 
 var (
@@ -43,7 +44,10 @@
 	if *local != "" {
 		gosrc.SetLocalDevMode(*local)
 	}
-	dir, err := gosrc.Get(http.DefaultClient, path, *etag)
+	c := &http.Client{
+		Transport: httputil.NewAuthTransport(&http.Transport{}),
+	}
+	dir, err := gosrc.Get(c, path, *etag)
 	if e, ok := err.(gosrc.NotFoundError); ok && e.Redirect != "" {
 		log.Fatalf("redirect to %s", e.Redirect)
 	} else if err != nil {