Sort tags so output is deterministic.

command/catalog_list_services.go

@@ -123,6 +123,7 @@ func (c *CatalogListServicesCommand) Run(args []string) int {
 		var b bytes.Buffer
 		tw := tabwriter.NewWriter(&b, 0, 2, 6, ' ', 0)
 		for _, s := range order {
+			sort.Strings(services[s])
 			fmt.Fprintf(tw, "%s\t%s\n", s, strings.Join(services[s], ","))
 		}
 		if err := tw.Flush(); err != nil {

command/catalog_list_services_test.go

@@ -102,7 +102,7 @@ func TestCatalogListServicesCommand_Run(t *testing.T) {
 		}
 
 		output := ui.OutputWriter.String()
-		if expected := "foo,bar"; !strings.Contains(output, expected) {
+		if expected := "bar,foo"; !strings.Contains(output, expected) {
 			t.Errorf("expected %q to contain %q", output, expected)
 		}
 	})