R4e's own delivery plan waited for ever in tier 1: the controller took every
module but build-agent's own from a referenced builder key, and only R4e's
builder and build modules, delivered by that same plan, write references.
The builder now says so in its bucket of instances; until it does, a walk asks
build-agent as before R4e, and an open walk waiting on a key the running
builder cannot reference is judged again at the next look.
jschoubben