test34.1 was failing with a configuration of
PreemptMode=suspend,gang
PreemptType=preempt/partition_prio
due to changes in commit f8fb79d5
That change appears to no longer be necessary and breaks a
valid configuration.

This is a special case. This change documents the way Slurm has
always worked.

Make sure that old step data is purged when a job is requeued.
Without this logic, if a job terminates abnormally then old step
data may be left in slurmctld. If the job is then requeued and
started on a different node, referencing that old job step data
can result in abnormal events. One specific failure mode is if
the job is requeued on a node with a different number of cores,
and the step terminated RPC arrives later, the job and step
bitmaps of allocated cores can differ in size generating an
abort.
bug 1660

TRES stuff

Conflicts:
	src/plugins/accounting_storage/mysql/as_mysql_job.c

Bug 1657

Bug 1618

Conflicts:
	src/slurmctld/reservation.c

cpu count.

"operator" will break the build.  So renaming it makes things work
correctly.

Original logic lacked check for NULL list pointer

The previous logic could deadlock with the log functions pthead_atfork()
functions depending upon the call order.