raft: Unset leader when starting election.
During election, there shouldn't be any leader. This change makes sure
that a server in candidate role always report leader as "unknown".
@@ -1649,6 +1649,7 @@ raft_start_election(struct raft *raft, bool leadership_transfer)
ovs_assert(raft->role != RAFT_LEADER);
+ raft->leader_sid = UUID_ZERO;
raft->role = RAFT_CANDIDATE;
/* If there was no leader elected since last election, we know we are
* retrying now. */
