select/cray: do the inventory immediately before each schedule

This puts the Basil inventory immediately before each (backfill) schedule. 

Having considered multiple alternatives, this is the most robust and least
wasteful solution. The reason is that ALPS keeps internal node state, which
can be changed
 * by the administrator (xtprocadmin),
 * by the node health checker programs (setting some nodes into 'suspect'),
 * by ALPS itself.

Tracking this periodically, e.g. every HealthCheckInterval, may mean to miss
some state changes. The result would not be a crash, but a subsequently
failed ALPS reservation, which would require to undo some of the slurm state.

Also added inventory to plugin/sched/wiki and wiki2 at get_node time

09_Cray-INVENTORY-directly-before-schedule.diff