ElasticConfiguration: Remove unused maxConnectionIdleUnit

Change-Id: Ib53d70bc3a5fb7d390c4f95f0f4ff79efb2a28b3

gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java

diff --git a/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java b/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java
index 4184ec0..8154b2d 100644
--- a/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java
+++ b/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java
@@ -41,7 +41,6 @@
   final boolean requestCompression;
   final long connectionTimeout;
   final long maxConnectionIdleTime;
-  final TimeUnit maxConnectionIdleUnit = TimeUnit.MILLISECONDS;
   final int maxTotalConnection;
   final int readTimeout;
   final String prefix;