(reap_children): Don't change C->file->command_state when dying.

(reap_children): Don't change C->file->command_state when dying.
Test it only after calling start_job_command for a new command line.
When no more cmds, just set C->file->update_status.
(start_job_command): When the last line is empty or under -n, set
C->file->update_status.
(start_waiting_job): Grok cs_not_started after start_job_command as success.
(new_job): Set C->file->update_status when there are no cmds.
(job_next_command): When out of lines, don't set CHILD->file->update_status or
CHILD->file->command_state.