cmd/gomote: add missing field to GRPC push

This change adds a missing directory setting to the GRPC push command.

For golang/go#48737
For golang/go#47521

Change-Id: I33daab7da55403df83033d0d4b6921bfeb10623c
Reviewed-on: https://go-review.googlesource.com/c/build/+/412374
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Carlos Amedee <carlos@golang.org>
diff --git a/cmd/gomote/push.go b/cmd/gomote/push.go
index 435261a..c2ae85f 100644
--- a/cmd/gomote/push.go
+++ b/cmd/gomote/push.go
@@ -558,8 +558,9 @@
 			return fmt.Errorf("unable to upload file to GCS: %s", err)
 		}
 		if _, err := client.WriteTGZFromURL(ctx, &protos.WriteTGZFromURLRequest{
-			GomoteId: name,
-			Url:      fmt.Sprintf("%s%s", resp.GetUrl(), resp.GetObjectName()),
+			GomoteId:  name,
+			Url:       fmt.Sprintf("%s%s", resp.GetUrl(), resp.GetObjectName()),
+			Directory: "go",
 		}); err != nil {
 			return fmt.Errorf("failed writing tarball to buildlet: %s", statusFromError(err))
 		}