ObjectStore: Add "need_journal" interface to make aware of journal device

Impl feature #9580

Signed-off-by: Haomai Wang <haomaiwang@gmail.com>
Merge pull request #2607 from yuyuyu101/wip-9580

ObjectStore: Add "need_journal" interface to make aware of journal devic...

Reviewed-by: Sage Weil <sage@redhat.com>