core: prevent transaction roll back on restore stateless vm

If template version update was made successfully when restoring
stateless VM, we didn't call setSucceeded(true) so the transaction was
rolled-back. So this patch adds the missing call.

Change-Id: I9714a4675225ef87ca4e1bdcf934aa87f02428fc
Signed-off-by: Arik Hadas <ahadas@redhat.com>