Remove unneeded nested MultiVersionModule class

This also align LuceneIndexModule with ElasticIndexModule which will
make it easier to refactor them to remove duplication.

Change-Id: Iaf0abdf0cfe5d9b0374d6f271da572bcd8832e4b
diff --git a/gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneIndexModule.java b/gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneIndexModule.java
index 5e85790..016f69e 100644
--- a/gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneIndexModule.java
+++ b/gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneIndexModule.java
@@ -74,7 +74,8 @@
 
     install(new IndexModule(threads));
     if (singleVersions == null) {
-      install(new MultiVersionModule());
+      bind(AbstractVersionManager.class).to(LuceneVersionManager.class);
+      listener().to(LuceneVersionManager.class);
     } else {
       install(new SingleVersionModule(singleVersions));
     }
@@ -87,12 +88,4 @@
         cfg.getInt("index", "maxTerms", BooleanQuery.getMaxClauseCount()));
     return IndexConfig.fromConfig(cfg);
   }
-
-  private static class MultiVersionModule extends LifecycleModule {
-    @Override
-    public void configure() {
-      bind(AbstractVersionManager.class).to(LuceneVersionManager.class);
-      listener().to(LuceneVersionManager.class);
-    }
-  }
 }