Should return error in case multisearch has error in response

[dqduc]

Sometime I met some responses in multisearch result:
{"error":"EsRejectedExecutionException[rejected execution of [org.elasticsearch.action.search.type.TransportSearchTypeAction$BaseAsyncAction$2]]"}

but the QueryResponse class dont have any field to determine if there're an exception occured in multi-search response.

It's good if QueryResponse has a property like "error" to determine this case.

[Mpdreamz]

Thanks @TinTin04 !

Checking .IsValid and ConnectionStatus now works the same on multisearch as it does on search.