Remove search.remote.* fallback and upgraders

Fallback settings were introduced in elastic#33413 where the
`search.remote.*` settings were generalized to `cluster.remote.*`.
This commit removes both the fallback settings and the upgraders
that were introduced in elastic#33537

Author: jkakavas

qa/full-cluster-restart/src/test/java/org/elasticsearch/upgrades/FullClusterRestartIT.java

@@ -26,7 +26,6 @@
 import org.elasticsearch.client.Response;
 import org.elasticsearch.client.ResponseException;
 import org.elasticsearch.client.RestClient;
-import org.elasticsearch.client.WarningFailureException;
 import org.elasticsearch.client.WarningsHandler;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.Booleans;
@@ -69,7 +68,6 @@
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.notNullValue;
-import static org.hamcrest.Matchers.startsWith;
 
 /**
  * Tests to run before and after a full cluster restart. This is run twice,
@@ -1055,27 +1053,10 @@ private void checkSnapshot(String snapshotName, int count, Version tookOnVersion
         assertEquals(singletonList(tookOnVersion.toString()), XContentMapValues.extractValue("snapshots.version", listSnapshotResponse));
 
         // Remove the routing setting and template so we can test restoring them.
-        try {
-            Request clearRoutingFromSettings = new Request("PUT", "/_cluster/settings");
-            clearRoutingFromSettings.setJsonEntity("{\"persistent\":{\"cluster.routing.allocation.exclude.test_attr\": null}}");
-            client().performRequest(clearRoutingFromSettings);
-        } catch (WarningFailureException e) {
-            /*
-             * If this test is executed on the upgraded mode before testRemoteClusterSettingsUpgraded,
-             * we will hit a warning exception because we put some deprecated settings in that test.
-             */
-            if (isRunningAgainstOldCluster() == false
-                && getOldClusterVersion().onOrAfter(Version.V_6_1_0) && getOldClusterVersion().before(Version.V_6_5_0)) {
-                for (String warning : e.getResponse().getWarnings()) {
-                    assertThat(warning, containsString(
-                        "setting was deprecated in Elasticsearch and will be removed in a future release! "
-                            + "See the breaking changes documentation for the next major version."));
-                    assertThat(warning, startsWith("[search.remote."));
-                }
-            } else {
-                throw e;
-            }
-        }
+
+        Request clearRoutingFromSettings = new Request("PUT", "/_cluster/settings");
+        clearRoutingFromSettings.setJsonEntity("{\"persistent\":{\"cluster.routing.allocation.exclude.test_attr\": null}}");
+        client().performRequest(clearRoutingFromSettings);
         client().performRequest(new Request("DELETE", "/_template/test_template"));
 
         // Restore

qa/full-cluster-restart/src/test/java/org/elasticsearch/upgrades/FullClusterRestartSettingsUpgradeIT.java

@@ -295,19 +295,12 @@ public void apply(Settings value, Settings current, Settings previous) {
                     ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING,
                     TransportSearchAction.SHARD_COUNT_LIMIT_SETTING,
                     RemoteClusterAware.REMOTE_CLUSTERS_SEEDS,
-                    RemoteClusterAware.SEARCH_REMOTE_CLUSTERS_SEEDS,
                     RemoteClusterAware.REMOTE_CLUSTERS_PROXY,
-                    RemoteClusterAware.SEARCH_REMOTE_CLUSTERS_PROXY,
                     RemoteClusterService.REMOTE_CLUSTER_SKIP_UNAVAILABLE,
-                    RemoteClusterService.SEARCH_REMOTE_CLUSTER_SKIP_UNAVAILABLE,
                     RemoteClusterService.REMOTE_CONNECTIONS_PER_CLUSTER,
-                    RemoteClusterService.SEARCH_REMOTE_CONNECTIONS_PER_CLUSTER,
                     RemoteClusterService.REMOTE_INITIAL_CONNECTION_TIMEOUT_SETTING,
-                    RemoteClusterService.SEARCH_REMOTE_INITIAL_CONNECTION_TIMEOUT_SETTING,
                     RemoteClusterService.REMOTE_NODE_ATTRIBUTE,
-                    RemoteClusterService.SEARCH_REMOTE_NODE_ATTRIBUTE,
                     RemoteClusterService.ENABLE_REMOTE_CLUSTERS,
-                    RemoteClusterService.SEARCH_ENABLE_REMOTE_CLUSTERS,
                     RemoteClusterService.REMOTE_CLUSTER_PING_SCHEDULE,
                     RemoteClusterService.REMOTE_CLUSTER_COMPRESS,
                     TransportCloseIndexAction.CLUSTER_INDICES_CLOSE_ENABLE_SETTING,
@@ -498,9 +491,6 @@ public void apply(Settings value, Settings current, Settings previous) {
                     DiscoveryUpgradeService.ENABLE_UNSAFE_BOOTSTRAPPING_ON_UPGRADE_SETTING
             )));
 
-    public static List<SettingUpgrader<?>> BUILT_IN_SETTING_UPGRADERS = Collections.unmodifiableList(Arrays.asList(
-            RemoteClusterAware.SEARCH_REMOTE_CLUSTER_SEEDS_UPGRADER,
-            RemoteClusterAware.SEARCH_REMOTE_CLUSTERS_PROXY_UPGRADER,
-            RemoteClusterService.SEARCH_REMOTE_CLUSTER_SKIP_UNAVAILABLE_UPGRADER));
+    public static List<SettingUpgrader<?>> BUILT_IN_SETTING_UPGRADERS = Collections.emptyList();
 
 }