Get snapshots when no state is available.

Get snapshots when no state is available.

With this patch we can restore the state of a state less job.
It may happen that there are more replication snapshots,
because no job state is known can not delete any snapshot.
Existing multiple replication-snapshot happens
when a node fails in middel of a replication
and then the VM is moved to another node.
That's why we have to test if we have a common base on both nodes.
Given this, we take this as a replica state.
After we have a state again, the rest of the snapshots can be deleted on the next run.