Fix issues when copying serialized thrift

Znode content should *always* be treated as bytes, never assume
utf-8 strings.

Signed-off-by: Raul Gutierrez S <rgs@itevenworks.net>
Reported-by: Aniruddha Laud <aniruddha@twitter.com>
Signed-off-by: Raul Gutierrez S <rgs@itevenworks.net>
Release version 0.97.0

Signed-off-by: Raul Gutierrez S <rgs@itevenworks.net>