consider the scenario(enable failsafe_mode):
0. node1(primary) - node2(replica)
1. stop all etcd nodes; wait ttl seconds; start all etcd nodes; (node2's failsafe will contain the info about node1)
2. switchover to node2; (node2's failsafe still contain the info about node1)
3. stop all etcd nodes; wait ttl seconds; start all etcd nodes;
4. node2 will demote because it consider node1 as primary
Resetting failsafe state when running as a primary fixes the issue.
