Fix ycsb measurement output

One simply should not close System.out ...

src/site/ycsb/Client.java

@@ -24,10 +24,7 @@ import org.apache.htrace.core.HTraceConfiguration;
 import org.apache.htrace.core.TraceScope;
 import org.apache.htrace.core.Tracer;
 
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.io.OutputStream;
+import java.io.*;
 import java.util.*;
 import java.util.Map.Entry;
 import java.util.concurrent.CountDownLatch;
@@ -219,7 +216,12 @@ public final class Client {
       OutputStream out;
       String exportFile = props.getProperty(EXPORT_FILE_PROPERTY);
       if (exportFile == null) {
-        out = System.out;
+        out = new FilterOutputStream(System.out) {
+          @Override
+          public void close() throws IOException {
+            flush();
+          }
+        };
       } else {
         out = new FileOutputStream(exportFile);
       }

src/site/ycsb/measurements/Measurements.java

@@ -52,8 +52,9 @@ public class Measurements {
   private static Measurements singleton = null;
   private static Properties measurementproperties = null;
 
-  public static void setProperties(Properties props) {
+  public static synchronized void setProperties(Properties props) {
     measurementproperties = props;
+    singleton = null;
   }
 
   /**