Fix problem updating job state_reason

This patch has two parts:
1. When a job is intially submitted, the Slurm was failing to set
   an initial reason for the job not starting.
2. After a job was submitted, it was sometimes failing to reset
   the job's reason. It was also failing to reset the "last_job_update"
   time, so something like "squeue -i1" would not get the new reason.
bug 3025