Currently there are two issues with serializing BulkByScrollResponse.
First, when deserializing from XContent, indexing exceptions and search
exceptions are switched. Additionally, search exceptions do no retain
the appropriate RestStatus code, so you must evaluate the status code
from the exception. However, the exception class is not always correctly
retained when serialized.
This commit adds tests in the failure case. Additionally, fixes the
swapping of failure types and adds the rest status code to the search
failure.
02622c1ef9