wwsh is not concurrency safe

[jlowellwofford]

This is mostly a note in case some one else runs into this kind of issue.

While writing some config management to wrap around warewulf, I learned that wwsh can have some strange behaviors when it's run concurrently. As a specific reproducer, make multiple wwsh "scripts" that define independent sets of nodes, e.g.

node new n01 ...
node set n01 --netdev eth0 ....
provision set n01 --vnfs=....
...

Cause them to run at the same time with: wwsh --nodhcp < script1 & wwsh --nodchp < script2. This will generally lead to nodes with parameters confused between them.

I have not investigated a root cause, but one hypothesis is that node id generation may not be atomic.