When rejoining shard leader election, we try to leave the election twice

When rejoining leader election, we tries to delete the leader election twice in Zookeeper.

This has no impact on the outcome of the leader election and this does not cause other failure. This is visible in logs (see bellow).

Scénario details

Method ZkController.rejoinShardLeaderElection() leaves the election by removing the sequential election node and the leader registration node. This is done directly from there by invoking prevContext.cancelElection().

Then LeaderElector.retryElection() does that again (this.context.cancelElection()) but the second time around always fails as the Zookeeper nodes were already removed by the first attempt.

Following log line is logged each time we invoke REJOINELECTION of a shard.
"No version found for ephemeral leader parent node, won't remove previous leader registration."