UpdateByQuery with a bad script results in a valid, successful NEST response.

[jonyadamit]

NEST/Elasticsearch.Net version: 2.4.1

Elasticsearch version: 2.3.3

Description of the problem including expected versus actual behavior:
UpdateByQuery with a bad script results in a valid, successful NEST response.

• IsValid property: Expected: false, Actual: true
• ServerError property: Expected: Object containing type of exception, root cause and caused by information. Actual: null
• Failures property is also null, but since the entire request failed, I suppose this is OK.

Steps to reproduce:
Invoke an UpdateByQuery request with an inline groovy script that fails to compile.
Original response from ES:

 {
   "error":{
      "root_cause":[
         {
            "type":"script_exception",
            "reason":"failed to compile groovy script"
         }
      ],
      "type":"script_exception",
      "reason":"Failed to compile inline script [ctx._source...] using lang [groovy]",
      "caused_by":{
         "type":"script_exception",
         "reason":"failed to compile groovy script",
         "caused_by":{
            "type":"multiple_compilation_errors_exception",
            "reason":"startup failed: xxx: 1: expecting EOF, found ')' @ line 1, column 113. 1 error"
         }
      }
   },
   "status":500
}

Provide DebugInformation (if relevant):

Valid NEST response built from a successful low level call on POST: /xxx/yyy/_update_by_query?size=1000
# Audit trail of this API call:
 - HealthyResponse: Node: http://somenode:9200/ Took: 00:00:00.0275072
# OriginalException: System.Net.WebException: The remote server returned an error: (500) Internal Server Error.
   at System.Net.HttpWebRequest.GetResponse()
   at Elasticsearch.Net.HttpConnection.Request[TReturn](RequestData requestData)

Sorry for being too busy to dig around and provide a PR for this.. keep up the wonderful work guys 😍

[gmarz]

Thanks for the great write up @jonyadamit 👍

Will look into this shortly.