Fixes Issue #212 Remove HTTPBadRequest error handling from all slices.

For each of the slices, when a hnl_http operation was performed, an http_response was included in most of the operations.  That response was then compared against instances of Net::HTTPBadRequest.  However, this functionality is handled in http_help.rb (handle_http_response).  The handle_http_response method would only ever return a result if the http_response was an instance of Net:HTTPSuccess.  Otherwise an error would be raised according to the http_response.