* MSQ: Controller checker should check for "closed" only.
Currently, the worker's controller checker will exit the worker if
the controller location is "closed" (no longer running) or if its location
is empty (i.e. location unknown).
This patch changes to only exit on "closed". We shouldn't exit on empty
location, because that may happen if the Overlord is slow to acknowledge the
location of a task.
* Fix test.
2b23d0b5b5