changed refresh to use POST instead of undocumented GET endpoint fix #378

Author: Mpdreamz

src/Nest.Tests.Integration/Reproduce/Reproduce211Tests.cs

@@ -42,7 +42,8 @@ public void NoSearchResults()
 
 			//indexing is NRT so issueing a search 
 			//right after indexing might not return the documents just yet.
-			this._client.Refresh(); 
+			var refreshResult = this._client.Refresh();
+			Assert.True(refreshResult.IsValid);
 
 			var results = this._client.Search<Post>(s => s
 				.Index(index)

src/Nest/ElasticClient-Refresh.cs

@@ -41,7 +41,7 @@ public IIndicesShardResponse Refresh<T>() where T : class
 		}
 		private IndicesShardResponse _Refresh(string path)
 		{
-			var status = this.Connection.GetSync(path);
+			var status = this.Connection.PostSync(path, null);
 			var r = this.Deserialize<IndicesShardResponse>(status);
 			return r;
 		}