Fix UI when no silences are present (#1090)

* Explicitly initialize silences list to avoid "null" JSON

* Wrap "No silences found" message in error box

* bindata fixup

api/api.go

@@ -624,7 +624,7 @@ func (api *API) listSilences(w http.ResponseWriter, r *http.Request) {
 		sils = append(sils, s)
 	}
 
-	var active, pending, expired, silences []*types.Silence
+	var active, pending, expired []*types.Silence
 
 	for _, s := range sils {
 		switch s.Status.State {
@@ -647,6 +647,9 @@ func (api *API) listSilences(w http.ResponseWriter, r *http.Request) {
 		return expired[i].EndsAt.After(expired[j].EndsAt)
 	})
 
+	// Initialize silences explicitly to an empty list (instead of nil)
+	// So that it does not get converted to "null" in JSON.
+	silences := []*types.Silence{}
 	silences = append(silences, active...)
 	silences = append(silences, pending...)
 	silences = append(silences, expired...)

ui/app/src/Views/SilenceList/Views.elm

@@ -52,7 +52,7 @@ tabView currentState ( state, silences ) =
 silencesView : Bool -> List Silence -> Html Msg
 silencesView showConfirmationDialog silences =
     if List.isEmpty silences then
-        div [] [ text "No silences found" ]
+        Utils.Views.error "No silences found"
     else
         ul [ class "list-group" ]
             (List.map (Views.SilenceList.SilenceView.view showConfirmationDialog) silences)