Fix shard logged in background lease renewal

The shard logged here is the leader shard but it should be the follower
shard since this background retention lease renewal is happening on the
follower side. This commit fixes that.

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/repository/CcrRepository.java

@@ -337,7 +337,7 @@ public class CcrRepository extends AbstractLifecycleComponent implements Reposit
                                             assert e instanceof ElasticsearchSecurityException == false : e;
                                             logger.warn(new ParameterizedMessage(
                                                             "{} background renewal of retention lease [{}] failed during restore",
-                                                            shardId,
+                                                            indexShard.shardId(),
                                                             retentionLeaseId),
                                                     e);
                                         }));