fix test to wipe lenient index first

core/src/test/java/org/elasticsearch/cluster/settings/ClusterSettingsIT.java

@@ -335,6 +335,7 @@ public class ClusterSettingsIT extends ESIntegTestCase {
             assertAcked(prepareCreate("test"));
             ensureGreen();
             client().admin().indices().prepareUpdateSettings("test").setSettings(Settings.builder().put("index.refresh_interval", "10")).execute().actionGet();
+            client().admin().indices().prepareDelete("test").get();
         } finally {
             // Restore the default so subsequent tests require units:
             assertFalse(Settings.getSettingsRequireUnits());