LU-10913 llog: add startcat for wrapped catalog

LU-10913 llog: add startcat for wrapped catalog

The osp_sync_thread loop for a llog_cat_process has a mistake.
When llog_cat_process has reached a bottom of catalog, the processing
restarts with 0. Which means a default processing. In this case a
catalog is wrapped and processing starts from a llh_cat_idx. But
records at the bottom were processed already, and were not cancelled
yet. The next message appears at log.
osp_sync_interpret()) reply req ffff8800123e3600/1, rc -2, transno 0

llog_cat_process support startcat index for processing catalog.
In this case the processing starts from startcat index. But if
catalog is wrapped startcat index is ignored.

The patch adds supporting of startcat index for wrapped catalog.

Signed-off-by: Alexander Boyko <c17825@cray.com>
Change-Id: Ie4e3ecf2532878578ae0463969115664e3589188
Cray-bug-id: LUS-6765
Reviewed-on: https://review.whamcloud.com/33749
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Sergey Cheremencev <c17829@cray.com>
Reviewed-by: Alexander Zarochentsev <c17826@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>