elasticsearch 1.3.1 null_value NPE (null pointer exception)

gistfile1.txt

export ES_HOST=http://localhost:9200
 
export ES_INDEX=test
 
# delete & recreate index with defaults
curl -XDELETE $ES_HOST/$ES_INDEX -s -o /dev/null
curl -XPUT $ES_HOST/$ES_INDEX -s -o /dev/null
 
# configure the mapping of the bug type in the test index
curl -XPUT $ES_HOST/$ES_INDEX/bug/_mapping -d '{
     "bug": {
         "properties": {
             "exception": {
                 "null_value": null,
                 "type": "integer"
             }
         }
     }
 }'