Documentation: Upgrade to Lucene 4.8

Change-Id: I259b29d6083cd2a479c417170d6c90c7c42c3b05
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/documentation/QueryDocumentationExecutor.java b/gerrit-server/src/main/java/com/google/gerrit/server/documentation/QueryDocumentationExecutor.java
index 763437f..b734007 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/documentation/QueryDocumentationExecutor.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/documentation/QueryDocumentationExecutor.java
@@ -46,7 +46,7 @@
   private static final Logger log =
       LoggerFactory.getLogger(QueryDocumentationExecutor.class);
 
-  private static final Version LUCENE_VERSION = Version.LUCENE_47;
+  private static final Version LUCENE_VERSION = Version.LUCENE_48;
 
   private IndexSearcher searcher;
   private QueryParser parser;
diff --git a/lib/asciidoctor/java/DocIndexer.java b/lib/asciidoctor/java/DocIndexer.java
index 45cad3d..96f3eb5 100644
--- a/lib/asciidoctor/java/DocIndexer.java
+++ b/lib/asciidoctor/java/DocIndexer.java
@@ -51,7 +51,7 @@
 import java.util.zip.ZipOutputStream;
 
 public class DocIndexer {
-  private static final Version LUCENE_VERSION = Version.LUCENE_47;
+  private static final Version LUCENE_VERSION = Version.LUCENE_48;
   private static final Pattern SECTION_HEADER = Pattern.compile("^=+ (.*)");
 
   @Option(name = "-o", usage = "output JAR file")