do not do active work if cfs update failed

do not do active work if cfs update failed

We ignored if the cluster state update failed and happily worked with
an empty state, resulting in strange actions, e.g., the removal of
all (not so) "stale" services or changing the all but the masters
node state to unknown.

Check on the update result and if failed, either do not get active,
or, if already active, skip the current round with the knowledge
that we only got here because the update failed but our lock renew
worked => cfs got already in a working and quorate state again -
(probably just a restart)

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
Reviewed-by: Dominik Csapak <d.csapak@proxmox.com>
Tested-by: Dominik Csapak <d.csapak@proxmox.com>