hook: Start vdsmd explicitly again

It's not really clear, but … If a dependency is brought down during a
service is queued, then the start job is canceled. And even if the
depdendency comes up again, the unit is not enqueued again.

Change-Id: I4796c96a8cd97d19beeafabc6c2a52b3817b9d12
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1156369
Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>