2e003adb added the ability for tasks using any_errors_fatal to fail
when there were unreachable hosts. However that patch used the running
unreachable hosts data rather than the results from the current task,
which causes failures when any run_once or BYPASS_HOST_LOOP task is hit
after an unreachable host causes a failure. This patch corrects that by
using the current set of results to determine if any hosts were
unreachable during the last task only.
Fixesansible/ansible-modules-core#4160