manager: make recovery actual state in FSM

manager: make recovery actual state in FSM

This basically makes recovery just an active state transition, as can
be seen from the regression tests - no other semantic change is
caused.

For the admin this is much better to grasp than services still marked
as "fence" when the failed node is already fenced or even already up
again.

Code-wise it makes sense too, to make the recovery part not so hidden
anymore, but show it was it is: an actual part of the FSM

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>