LU-16251 obdclass: fill jobid in a safe way

LU-16251 obdclass: fill jobid in a safe way

jobid_interpret_string() does not fill jobid in an atomic way.
So in lustre_get_jobid() give it a buffer first, then copy the
buffer to jobid as a whole.

Signed-off-by: Lei Feng <flei@whamcloud.com>
Change-Id: Ib8f6aaa93df31867982a0d142f33d7374a27234f
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/48915
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>