Instead of providing and retaining a thread count in
the worker and action engine executors and checking it
and handling the none case, we can just let the future
types handle this already (which they already do). And
when displaying this information in the worker banner
use a new future executor attribute that is the maximum
number of workers that will be ever created.
Change-Id: I765c22936b53cdbb8a90195a764d4c67bcc3f34b
22fd32fb55