Implementations of IOperation.GetValue hide XError response

Various implementations of IOperation<T>.GetValue filter the response by whether or not a status of Success was returned by-passing the reading of the body. In cases where the status is say "eaccess" and a XError response of 

{"error":{"context":"Authorization failure: can't execute GET_CLUSTER_CONFIG operation without the SystemSettings privilege","ref":"3ce048e8-b59f-4990-ca84-78a2ff5e809a"}} 

is returned by the server in the body, its not parsed and deserialized. The XError details should be returned to the caller or as part of a thrown exception and perhaps (likely) logged.

Here is an example (there are more):

https://github.com/couchbase/couchbase-net-client/blob/master/src/Couchbase/Core/IO/Operations/Legacy/Config.cs#L43