Some exceptions omit a server reply. E.g. one found while implementing transaction spec tests:

https://github.com/mongodb/mongo-cxx-driver/blob/r3.3.1/src/mongocxx/cursor.cpp#L55

Should instead use mongoc_cursor_error_document and include the reply document if one is returned.

From scanning through it looks like there might be more cases throwing that are not including the server reply in the exception. We should audit all such cases and add the reply where possible.