apache with mod_wsgi takes care of starting the app.
If the role is first ran with the defaults, the ara systemd service
will be running.
If we re-run the role and choose an apache deployment, we need to make
sure we're disabling it.
What this boils down to -- let's always set up the systemd service
but start it or disable it according to what we need to deploy.
Change-Id: I8fceed417d766a28564ad88a972de4f38c1b44ac
49bd5e1afa