rgw: new RGWRados::time_log_list interface to cls_log_list

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: metadata accessor to RGWRados::time_log_list

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

Conflicts:

	src/rgw/rgw_metadata.cc
rgw: show metadata log through radosgw-admin

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: cls_log_trim boundary change

end_time is not inclusive

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