Suppress unused parameter warning

Change-Id: I677ec8eed7be2b08be7efbb5dad0b71b555c0063
diff --git a/src/main/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java b/src/main/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java
index ebf1eec..180d135 100644
--- a/src/main/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java
+++ b/src/main/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java
@@ -162,5 +162,6 @@
     }
   }
 
-  protected void configureHttpClientBuilder(HttpAsyncClientBuilder httpClientBuilder) {}
+  protected void configureHttpClientBuilder(
+      @SuppressWarnings("unused") HttpAsyncClientBuilder httpClientBuilder) {}
 }