Continue removing select_g_alter_node_cnt() calls.

The err_cpus return return for:
select_g_select_nodeinfo_get(node_ptr->select_nodeinfo,
                             SELECT_NODEDATA_SUBCNT,
                             NODE_STATE_ERROR, &err_cpus);
is always zero for non-select/bluegene plugins, so this whole
function can be drastically simplified.

Move the node_ptr->name check up front. Invert the remaining logic,
which makes it clear any nodes in DRAIL/FAIL/DOWN are what will
trigger the clusteracct_storage_g_node_down call.

SELECT_GET_NODE_SCALING is always 1 for non-select/bluegene
plugins. Pack it directly. On a future RPC layer this should be
removed once the client commands have been updated as well.

SELECT_APPLY_NODE_MAX_OFFSET is a no-op on non-bluegene
plugins, so we can now just pack total_nodes directly.

Similarly, update_part does not need to translate a
min node count into a midplane count anymore.

Just strip out all HAVE_BG code here to remove the
select_g_alter_node_cnt() calls buried within.

select_p_alter_node_cnt() is a no-op here for
every non-bluegene select plugin.

This is always zero on non-bluegene select plugins:
select_g_select_nodeinfo_get(node_ptr->select_nodeinfo,
                             SELECT_NODEDATA_SUBCNT,
                             NODE_STATE_ERROR,
                             &err_cpus);

So all of this code can be collapsed down to three lines.

Only used by select/bluegene, which is being removed.

Still need to remove all calling paths into select_g_alter_node_cnt,
so leave stubbed out for now.

srun would not return an exit code if a previous task exited before a
latter task exited with a signal.

If multiple tasks exit with a signal, srun returns the highest signal.

Partially reverts commit 04b449e1 -- the setting of local_global_rc
to NO_VAL as srun doesn't need to know whether it's been set or not
anymore. srun always sets the signal if a task exited with a signal.

Bug 5083

Avoid left-over test input file

src/plugins/ and src/common/assoc_mgr.c are still left to convert.

No functional change.

Bug 4999.

There were two code paths building an allocation response by calling
its own static _build_alloc_msg() function:

1. src/slurmctld/proc_req.c
2. src/slurmctld/srun_comm.c

These two functions diverged and both had members that were not filled
in but were filled in the other. This patch makes it so we change the
signature of the one in proc_req.c to make it extern and then in
srun_comm.c we call this newly common function.

Also added cpu_freq_[min|max|gov] members in the common one since these
were the only members missing in proc_req.c function (the one in
srun_comm.c had more members missing, like all the ntasks_per*, account,
qos or resv_name).

Bug 4999.

Update slurm.spec and slurm.spec-legacy as well

Only trust MUNGE signed values, unless the RPC was signed by
SlurmUser or root.

CVE-2018-10995.

Already vetted by slurmctld/slurmd, no need to re-check here.

Do not defer until later, and do not potentially miss out on proper
validation of the user_name field which can lead to improper authentication
handling.

CVE-2018-10995.

If the auth value (from MUNGE) does not match the requested value,
ensure it is listed as a valid extended gid for that user instead.

Bug 5038.