cls_statelog: fix a few issues

Issues that came up when developed the unitest

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

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
cls_statelog: pass in timestamp

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: internal api for statelog objclass

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: specialized obj zone copy state for statelog

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: fix check_state call

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: OpState internal api

Add new higher level functions to set, renew, list, and remove
logged operation state.

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
radosgw-admin: interface to control ops state

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