More gracefully handle batch launch failure

If a batch job launch request can not be built (the script file
is missing, a credential can not be created, or the user does
not exist on the selected compute node), then cancel the job
in a graceful fashion. Previously, the bad RPC would be sent to
the compute node and that node DRAINED.
see bug 807
Jobs hidden only if ALL partitions are hidden

Only if ALL of their partitions are hidden will a job be hidden by default.
bug 812
Cosmetic mods
Run EpilogSlurmctld for jobs killed in reconfig

Run EpilogSlurmctld for a job is killed during slurmctld reconfiguration.
bug 806
Merge branch 'slurm-14.03'

Conflicts:
	src/slurmctld/job_scheduler.c