[gold] Return valid JSON when deleting.

It will keep our endpoints more consistent to always return valid JSON.

Change-Id: I32b09ec2a3ba6b50fd31c5c1174594480a54d801
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/263940
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
diff --git a/golden/go/web/web.go b/golden/go/web/web.go
index 983769a..436d270 100644
--- a/golden/go/web/web.go
+++ b/golden/go/web/web.go
@@ -837,8 +837,8 @@
 		return
 	} else if numDeleted == 1 {
 		sklog.Infof("Successfully deleted ignore with id %s", id)
-		if _, err := w.Write([]byte("ok")); err != nil {
-			sklog.Warningf("error responding ok to ignore deletion: %s", err)
+		if _, err := w.Write([]byte(`{"deleted": "true"}`)); err != nil {
+			sklog.Warningf("error responding success to ignore deletion: %s", err)
 		}
 	} else {
 		sklog.Infof("Deleting ignore with id %s from ignorestore failed", id)