Rename cluster settings following new 2.x convention

Previously the setting was `cluster.initial_master_nodes` and has since
changed to `cluster.initial_cluster_manager_nodes`.  This was causing
issues due to a bug in the fallback method that has been fixed in
OpenSearch, but getting ahead of this change before its needed.

See related opensearch-project/OpenSearch#2779

Signed-off-by: Peter Nied <petern@amazon.com>

src/test/java/org/opensearch/security/test/helper/cluster/ClusterHelper.java

@@ -366,7 +366,7 @@ private Settings.Builder getMinimumNonSecurityNodeSettingsBuilder(final int node
                 .put("path.logs", "./target/data/"+clustername+"/logs")
                 .put("node.max_local_storage_nodes", nodeCount)
                 //.put("discovery.zen.minimum_master_nodes", minMasterNodes(masterTcpPorts.size()))
-                .putList("cluster.initial_master_nodes", masterTcpPorts.stream().map(s->"127.0.0.1:"+s).collect(Collectors.toList()))
+                .putList("cluster.initial_cluster_manager_nodes", masterTcpPorts.stream().map(s->"127.0.0.1:"+s).collect(Collectors.toList()))
                 //.put("discovery.zen.no_master_block", "all")
                 //.put("discovery.zen.fd.ping_timeout", "5s")
                 .put("discovery.initial_state_timeout","8s")

tools/install_demo_configuration.sh

@@ -382,7 +382,7 @@ else
 	if [ "$cluster_mode" == 1 ]; then
         echo "network.host: 0.0.0.0" | $SUDO_CMD tee -a "$OPENSEARCH_CONF_FILE" > /dev/null
         echo "node.name: smoketestnode" | $SUDO_CMD tee -a "$OPENSEARCH_CONF_FILE" > /dev/null
-        echo "cluster.initial_master_nodes: smoketestnode" | $SUDO_CMD tee -a "$OPENSEARCH_CONF_FILE" > /dev/null
+        echo "cluster.initial_cluster_manager_nodes: smoketestnode" | $SUDO_CMD tee -a "$OPENSEARCH_CONF_FILE" > /dev/null
     fi
 fi