Adapt to the latest Index interface in stable-3.5

Change I140c88125b has introduced an additional insert() method
for optimising the off-line reindex for Lucene.

Map the insert() method with replace() which would produce the
same effect of creating a index entry.

Change-Id: I6f2e6c45bf2cf68ebd7d8dc3fa19083c59bced83

src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java

diff --git a/src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java b/src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
index 562464d..90ce18b 100644
--- a/src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
+++ b/src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
@@ -152,6 +152,11 @@
   }
 
   @Override
+  public void insert(V obj) {
+    replace(obj);
+  }
+
+  @Override
   public Schema<V> getSchema() {
     return schema;
   }