Bug 182680 Use feature of new Aggregation framework of Data Engine.
DataEngine will implement new aggregation framework in 2.2.0RC0. After the implementation is finished Engine should go ahead to use new column bindings in definition of map/highlight.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineLogger.java
rootLogger.removeHandler( sharedHandler );
		sharedHandler.close( );
		sharedHandler = null;
		if ( fileLogger != null )
		{
			closeFileLogger( fileLogger );
			fileLogger = null;
		}
		userLogger = null;
	}
	/**
	 * Change the log level to the newLevel
	 * @param newLevel - new log level
	 */
	public static void changeLogLevel( Level newLevel )
	{
		if ( newLevel != null )
		{
			if ( userLogger != null )
			{
				if ( newLevel != Level.OFF && fileLogger == null
						&& dirName != null )
				{
					fileLogger = createFileLogger( dirName );
					if ( fileLogger != null )
					{
						sharedHandler.setSharedLogger( fileLogger );
					}
				}
			}