Restore ConcurrentMergeScheduler (important for spin disks)

Change-Id: I1312be23cdfc41537aca7624c2819381847b6162
Signed-off-by: Dawid Pakuła <zulus@w3des.net>
diff --git a/core/plugins/org.eclipse.dltk.core.index.lucene/src/org/eclipse/dltk/internal/core/index/lucene/IndexContainer.java b/core/plugins/org.eclipse.dltk.core.index.lucene/src/org/eclipse/dltk/internal/core/index/lucene/IndexContainer.java
index 9f4e3d0..c13f08c 100644
--- a/core/plugins/org.eclipse.dltk.core.index.lucene/src/org/eclipse/dltk/internal/core/index/lucene/IndexContainer.java
+++ b/core/plugins/org.eclipse.dltk.core.index.lucene/src/org/eclipse/dltk/internal/core/index/lucene/IndexContainer.java
@@ -25,7 +25,6 @@
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.IndexWriterConfig.OpenMode;
-import org.apache.lucene.index.SerialMergeScheduler;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.SearcherFactory;
 import org.apache.lucene.search.SearcherManager;
@@ -135,8 +134,8 @@
 		IndexWriterConfig config = new IndexWriterConfig(new SimpleAnalyzer());
 		config.setUseCompoundFile(true);
 		// we already are on separate thread
-		SerialMergeScheduler sheduler = new SerialMergeScheduler();
-		config.setMergeScheduler(sheduler);
+		// SerialMergeScheduler sheduler = new SerialMergeScheduler();
+		// config.setMergeScheduler(sheduler);
 		config.setOpenMode(OpenMode.CREATE_OR_APPEND);
 		config.setCommitOnClose(false);
 		return new IndexWriter(indexDir, config);