LU-14098 obdclass: try to skip corrupted llog records

LU-14098 obdclass: try to skip corrupted llog records

if llog's header or record is found corrupted, then
ignore the remaining records and try with the next one.

Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: If47ec1fc1e2eaf64be7ba08d3aa9c2b93903c0cf
Reviewed-on: https://review.whamcloud.com/40754
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Mike Pershin <mpershin@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>