Upgrade to Elasticsearch 6.2.4

Closes gh-13178

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/elasticsearch/rest/RestClientAutoConfiguration.java

@@ -62,12 +62,13 @@ public class RestClientAutoConfiguration {
 
 	@Bean(destroyMethod = "close")
 	@ConditionalOnMissingBean
-	public RestClient restClient() {
-		RestClientBuilder builder = configureBuilder();
+	public RestClient restClient(RestClientBuilder builder) {
 		return builder.build();
 	}
 
-	protected RestClientBuilder configureBuilder() {
+	@Bean
+	@ConditionalOnMissingBean
+	public RestClientBuilder restClientBuilder() {
 		HttpHost[] hosts = this.properties.getUris().stream().map(HttpHost::create)
 				.toArray(HttpHost[]::new);
 		RestClientBuilder builder = RestClient.builder(hosts);
@@ -90,8 +91,9 @@ public class RestClientAutoConfiguration {
 
 		@Bean
 		@ConditionalOnMissingBean
-		public RestHighLevelClient restHighLevelClient(RestClient restClient) {
-			return new RestHighLevelClient(restClient);
+		public RestHighLevelClient restHighLevelClient(
+				RestClientBuilder restClientBuilder) {
+			return new RestHighLevelClient(restClientBuilder);
 		}
 
 	}

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -59,7 +59,7 @@
 		<embedded-mongo.version>2.0.3</embedded-mongo.version>
 		<flyway.version>5.0.7</flyway.version>
 		<freemarker.version>2.3.28</freemarker.version>
-		<elasticsearch.version>5.6.9</elasticsearch.version>
+		<elasticsearch.version>6.2.4</elasticsearch.version>
 		<glassfish-el.version>3.0.0</glassfish-el.version>
 		<groovy.version>2.4.15</groovy.version>
 		<gson.version>2.8.4</gson.version>