Correction in logic issuing call to account for change in job time limit

I don't believe save_time_limit was redundant.  At least in this case:

if (qos_ptr && (qos_ptr->flags & QOS_FLAG_NO_RESERVE)){
    if (orig_time_limit == NO_VAL)
        orig_time_limit = comp_time_limit;
    job_ptr->time_limit = orig_time_limit;
[...]

So later, when updating the db,

    if (save_time_limit != job_ptr->time_limit)
        jobacct_storage_g_job_start(acct_db_conn,
                        job_ptr);
will cause the db to be updated, while,

        if (orig_time_limit != job_ptr->time_limit)
        jobacct_storage_g_job_start(acct_db_conn,
                        job_ptr);

will not because job_ptr->time_limit now equals orig_time_limit.
Merge branch 'slurm-2.5'