Wait for corosync to be ready before doing anything

On the initial run, it takes 20-30 seconds before corosync is ready to
accept changes with "crm configure". So wait for that before we continue
(and apply crm-initial.conf, for instance).
For per_node STONITH, have each node configure its own resources only

We have some races when creating STONITH resources because nodes are
creating resources at the same time. It turns out that, in the case of
crowbar, we can have each node configure its own resources only because
we know all nodes will run the code.