Ensure testAckedIndexing uses disruption index settings

AbstractDisruptionTestCase set a lower global checkpoint sync interval setting, but this was ignored by
testAckedIndexing, which has led to spurious test failures

Relates elastic#41068, elastic#38931

Author: ywelsch

server/src/main/java/org/elasticsearch/indices/recovery/PeerRecoveryTargetService.java

@@ -356,7 +356,7 @@ private StartRecoveryRequest getStartRecoveryRequest(final RecoveryTarget recove
             logger.trace("{} preparing for file-based recovery from [{}]", recoveryTarget.shardId(), recoveryTarget.sourceNode());
         } else {
             logger.trace(
-                "{} preparing for sequence-number-based recovery starting at local checkpoint [{}] from [{}]",
+                "{} preparing for sequence-number-based recovery starting at sequence number [{}] from [{}]",
                 recoveryTarget.shardId(),
                 startingSeqNo,
                 recoveryTarget.sourceNode());

server/src/test/java/org/elasticsearch/discovery/ClusterDisruptionIT.java

@@ -119,6 +119,7 @@ public void testAckedIndexing() throws Exception {
 
         assertAcked(prepareCreate("test")
             .setSettings(Settings.builder()
+                .put(indexSettings())
                 .put(IndexMetaData.SETTING_NUMBER_OF_SHARDS, 1 + randomInt(2))
                 .put(IndexMetaData.SETTING_NUMBER_OF_REPLICAS, randomInt(2))
             ));