Fix NodeStats for 0.90+

Author: NickCraver

src/Nest/Domain/Stats/NodeStats.cs

@@ -19,7 +19,7 @@ public class NodeStats
         public string Hostname { get; internal set; }
 
         [JsonProperty("indices")]
-        public Dictionary<string, NodeStatsIndexes> Indices { get; internal set; }
+        public NodeStatsIndexes Indices { get; internal set; }
 
         [JsonProperty("os")]
         public OSStats OS { get; internal set; }