rgw: fix bucket link

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: admin, fix object rm, object unlink

Broken due to recent changes in radosgw-admin.

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: admin, fix policy command

radosgw-admin policy command wasn't returning anything

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>