regarding http://dev.kohanaframework.org/issues/4695

the way HTTP_Exceptions are handled ...exceptionally in the Kohana/Request/Client/Internal.php makes it difficult to override their presentation when exceptions are thrown before Client->execute() such as the case of Route::Filters()

This change allows request to call the overloaded version of the function instead of always forcing Kohana_Exception::response(), while still using it as the default in the case of non kohana exceptions.