LU-16376 obdclass: NUL terminate long jobid strings

LU-16376 obdclass: NUL terminate long jobid strings

It appears that some jobid names can be sent that are using the full
32-byte size, rather than containing an embedded NUL terminator. This
caused errors in lprocfs_job_stats_log() when it overflowed.

If there is no NUL terminator in lustre_msg_get_jobid() then add one
if not found within the buffer, so that the rest of the code doesn't
have to deal with unterminated strings.

This potentially exposes a larger issue that other places may not be
handling the unterminated string properly either, which needs to be
addressed separately on both the client and server.  Terminating the
jobid to 31 chars only on the client does not totally solve the issue,
since there will still be older clients that are not doing this, so
the server needs to handle this in any case.

Lustre-change: https://review.whamcloud.com/49351
Lustre-commit: 9eba5d57297f807fddf046356c846478bbf232f4

Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I4c05fabdacb6a0bbf6477d3601a628fe1f3ebbe5
Reviewed-by: Feng Lei <flei@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49490
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>