BulkItemResponse returns status code instead of status name

In commit fafeb3a, we've refactored REST response handling logic
and returned HTTP status names instead of HTTP status codes for
bulk item responses. With this commit we restore the original
behavior.

Checked with @bleskes.

core/src/main/java/org/elasticsearch/action/bulk/BulkItemResponse.java

@@ -51,12 +51,12 @@ public class BulkItemResponse implements Streamable, StatusToXContent {
         builder.startObject(opType);
         if (failure == null) {
             response.toXContent(builder, params);
-            builder.field(Fields.STATUS, response.status());
+            builder.field(Fields.STATUS, response.status().getStatus());
         } else {
             builder.field(Fields._INDEX, failure.getIndex());
             builder.field(Fields._TYPE, failure.getType());
             builder.field(Fields._ID, failure.getId());
-            builder.field(Fields.STATUS, failure.getStatus());
+            builder.field(Fields.STATUS, failure.getStatus().getStatus());
             builder.startObject(Fields.ERROR);
             ElasticsearchException.toXContent(builder, params, failure.getCause());
             builder.endObject();