Certain services will shutdown gracefully and so they may not be dead by the
time this task is run.  Those services should not be explicitly killed since
they may need to do things like finish a grading run or other instructor tasks.

They're in here twice.

Adding this so we can do a non-blocking call to stop services
which will be useful when we call this as a part of the ansible
run that kicks off Minos.

In order to support --check we need to ensure that registered
vars exist before checking their stdout. Otherwise ansible
errors out.