Fix JSON structure for cluster stats

See olivere#229

CONTRIBUTORS

@@ -25,6 +25,7 @@ Junpei Tsuji [@jun06t](https://github.com/jun06t)
 Maciej Lisiewski [@c2h5oh](https://github.com/c2h5oh)
 Mara Kim [@autochthe](https://github.com/autochthe)
 Medhi Bechina [@mdzor](https://github.com/mdzor)
+Naoya Tsutsumi [@tutuming](https://github.com/tutuming)
 Nicholas Wolff [@nwolff](https://github.com/nwolff)
 Orne Brocaar [@brocaar](https://github.com/brocaar)
 Ryan Schmukler [@rschmukler](https://github.com/rschmukler)

cluster_stats.go

@@ -238,7 +238,7 @@ type ClusterStatsIndicesPercolate struct {
 // ---
 
 type ClusterStatsNodes struct {
-	Count    *ClusterStatsNodesCounts       `json:"counts"`
+	Count    *ClusterStatsNodesCount        `json:"count"`
 	Versions []string                       `json:"versions"`
 	OS       *ClusterStatsNodesOsStats      `json:"os"`
 	Process  *ClusterStatsNodesProcessStats `json:"process"`
@@ -247,7 +247,7 @@ type ClusterStatsNodes struct {
 	Plugins  []*ClusterStatsNodesPlugin     `json:"plugins"`
 }
 
-type ClusterStatsNodesCounts struct {
+type ClusterStatsNodesCount struct {
 	Total      int `json:"total"`
 	MasterOnly int `json:"master_only"`
 	DataOnly   int `json:"data_only"`

cluster_stats_test.go

@@ -23,6 +23,12 @@ func TestClusterStats(t *testing.T) {
 	if res.ClusterName == "" {
 		t.Fatalf("expected a cluster name; got: %q", res.ClusterName)
 	}
+	if res.Nodes == nil {
+		t.Fatalf("expected nodes; got: %v", res.Nodes)
+	}
+	if res.Nodes.Count == nil {
+		t.Fatalf("expected nodes count; got: %v", res.Nodes.Count)
+	}
 }
 
 func TestClusterStatsURLs(t *testing.T) {