[triage] Omit the product if empty

The wpt-metadata repository expects that the product field will be
omitted if empty, not written as an empty string (the current behavior).
Fix this by marking it omitempty.

Author: stephenmcgruer

shared/metadata.go

@@ -34,7 +34,7 @@ type MetadataLinks []MetadataLink
 // META.yml file, which lists an external reference, optionally
 // filtered by product and a specific test.
 type MetadataLink struct {
-	Product ProductSpec          `yaml:"product" json:"product,omitempty"`
+	Product ProductSpec          `yaml:"product,omitempty" json:"product,omitempty"`
 	URL     string               `yaml:"url"     json:"url"`
 	Results []MetadataTestResult `yaml:"results" json:"results,omitempty"`
 }

shared/metadata_test.go

@@ -28,6 +28,9 @@ links:
       subtest: Something should happen
       status: FAIL
     - test: c.html
+  - url: https://github-issue.com/1234
+    results:
+    - test: d.html
 `)
 	yaml.Unmarshal(metadataInBytes, &metadata)
 	acutalInBytes, _ := yaml.Marshal(metadata)